Observations: How to make them quickly and use them effectively

In competitive programming, the success of a programmer hinges crucially on their ability to observe and analyze problems. This observational phase is a critical yet often undervalued aspect of problem-solving, forming the bedrock upon which efficient solutions are built. It involves not just a superficial understanding of the problem statement, but a deeper analysis of its nuances and underlying patterns. Effective observation can mean the difference between identifying the most suitable algorithms and approaches, or missing out on key insights that could lead to optimal solutions.

Furthermore, the skill of observation extends to recognizing potential pitfalls, understanding constraints, and predicting the behavior of different approaches. This comprehensive strategy not only aids in tailoring solutions more precisely but also in anticipating challenges. For aspiring competitive programmers, refining observational skills is thus as vital as enhancing coding abilities, as it significantly influences the journey from problem understanding to solution implementation. Today, I’ll discuss some tips that can help speed up your observation phase. 

Time Complexity and Constraints

The key to unlocking the most efficient solutions lies in a keen understanding and analysis of the problem's constraints. Constraints are not just arbitrary numbers; they are critical clues pointing towards the nature of the expected solution. The first and most important tip I can offer is to pay close attention to these constraints. They reveal much about the problem, guiding you towards specific approaches and techniques.

It's essential to remember that problem setters design these constraints deliberately. They typically provide just enough time for an optimally efficient solution, with few exceptions. For example, older USACO problems sometimes presented the same problems in higher divisions as in lower ones but with increased limits. In such cases, the time allowed may be more generous than necessary. However, in most scenarios, it’s crucial to work within the strict confines of these constraints.

Here’s a detailed strategy to fully harness the power of problem constraints:

• Document Every Constraint: Start by systematically noting down every constraint applied to each variable. This includes constraints on the number of elements, the range of values these elements can take, and any specific limitations like the values of coordinates. Understanding these constraints helps in framing a precise and efficient approach to the problem.

• Focus on Small Limits: Small limits often hold significant implications. For instance, if you encounter a problem where N = 10^5 and K = 10, it's a strong hint towards a solution with O(NK) or O(NK^2) complexity. Small limits like these are an invitation to creatively nest loops and explore solutions that might otherwise be deemed too complex or inefficient.

• Don’t Overlook Large Limits: Conversely, large limits also carry their own messages. A limit as high as 10^18, for example, suggests that logarithmic approaches might be necessary. Such large numbers typically require strategies that reduce the computational load, such as utilizing logarithms to manage these limits effectively. For example, in the problem Searching For Soulmates, (spoilers) it’s easy to assume that an O(1) solution is necessary, since the constraints are so large, however, this is not necessarily the case. 

Let’s dive into some specific limits and what they could imply:

• N = 1e5, 2e5, 5e5, etc: This range of limits, while offering minimal direct guidance, still tells us something important. It essentially rules out any solution that would involve nested iterations through N due to time constraints. This nudges us towards considering algorithms that operate linearly or include some logarithmic components. If these are coupled with smaller limits, it opens up possibilities to nest loops with N and the smaller limits, prompting thoughts towards such combined approaches. Here, the concept of amortization, which involves spreading out computational costs, becomes extremely relevant; also think about scenarios where loops of N can be nested, but through smart amortization, the overall complexity remains O(N).

• N = 5,000 - 7,500: This is a distinct and telling limit. It essentially warns against attempting algorithms with O(N^2 log N) complexity, as they are likely to cause timeouts. Instead, the focus should shift to O(N^2) algorithms. Here, the aim is to find solutions that involve iterating through N twice in nested loops, without incorporating additional logarithmic factors.

• N = 1,000 - 2,000: In this range, while logarithmic factors such as sorting or binary search are possible, they aren't always necessary. Your algorithmic considerations can include but aren't limited to, methods that incorporate log N factors.

• N = 500: Like the 5,000 - 7,500 range, this limit also suggests an O(N^3) approach. Solutions here should ideally be tailored to fit precisely within this complexity range.

• N = 200: At this level, you are likely looking at either O(N^3) or O(N^3 log N) algorithms. This is a nuanced distinction but an important one in terms of the complexity you can afford in your solution.

• N = 20: This specific limit often indicates the use of bit manipulation, with bitmasking being a prevalent technique. For higher levels like gold and above, this usually translates into bitmask dynamic programming. For lower levels like silver and bronze, it often means iterating over all subsets.

• N = 10: Though not as common, this constraint typically implies solutions involving permutations of elements.

In sum, a nuanced understanding and interpretation of constraints in competitive programming is not just beneficial; it's essential. These constraints guide you towards the most appropriate and efficient algorithms and techniques for a given problem. By tailoring your approach based on these constraints, you can develop solutions that are not only effective but also elegantly aligned with the problem's requirements.

Forced/Optimal Actions in Problem-Solving

An invaluable strategy is to focus on identifying 'forced' actions within a problem. These are actions or steps that you are compelled to take, given the constraints and nature of the problem. They represent truths or necessities that are unchangeable within the context of the problem. By recognizing these forced actions, you establish a robust foundation for further observations and analysis. This approach not only simplifies complex problems but also streamlines the path to finding a solution.

To better grasp this concept, let's delve into an illustrative example. Imagine a scenario where you have an array of positive integers, and your goal is to reduce every element in the array to zero. The only operation available to you is to decrement two adjacent elements by one, and you can repeat this operation as many times as necessary.

At first glance, the problem might seem daunting, with multiple potential starting points for operations. However, upon closer examination, you realize there are 'forced' operations. Consider the leftmost integer in the array, let's say it's 'x'. You are inevitably required to apply the operation to the first two integers 'x' times to reduce the leftmost integer to zero. This is a forced action – one without which the leftmost element can never become zero. Recognizing this forced operation is pivotal. It leads to the realization that all subsequent operations are similarly 'forced', aimed at continually reducing the leftmost non-zero element to zero. By identifying this pattern of forced actions, you effectively outline the entire solution methodology for the problem.

Optimal Actions: A Variant of Forced Actions

Another angle to consider is identifying actions that are 'optimal', which is a common variation in problem-solving. These are actions that, while not strictly forced by the problem's constraints, represent the most efficient path to a solution.

Let’s again take the example of the "Searching For Soulmates" problem. The following content will spoil the problem, so if you have not solved it yet and desire to do so on your own, I recommend skipping past this next part.

Focus on the division operation. It becomes evident that it is always optimal to add at most once before each division. Adding more than once is less efficient as it could be replaced with a more optimal sequence: adding less and dividing earlier. For instance, a sequence like "+ + /" is more effectively executed as “/ +”.

In essence, you are 'forced' to add either 0 or 1 times before a division because it is never optimal to add more. This insight significantly narrows down the range of possible action sequences, guiding you closer to the correct solution. Recognizing these optimal actions is about understanding the inherent efficiency of certain steps within the problem's framework.

In conclusion, focusing on forced and optimal actions in problem-solving is a powerful strategy in competitive programming. It simplifies complex problems by highlighting necessary or highly efficient steps. This approach not only aids in establishing a clear direction for solving problems but also enhances the overall efficiency and effectiveness of the solution. By mastering the art of identifying these actions, you can significantly improve your problem-solving skills and performance in competitive programming.

The Vital Role of Best/Worst Case Analysis in Competitive Programming

A critical and often game-changing approach is the analysis of best and worst-case scenarios for any given problem. This method is particularly effective in problems where the objective is to derive the best possible outcome. In fact, there are a lot of problems (even in USACO) where the best or worst case solution is actually the answer to the entire problem! Delving into the best and worst cases not only provides a starting point for your problem-solving journey but also offers a framework within which you can examine how the actual solution may deviate from these extremes.

Take, for instance, this problem from Codeforces. You are presented with two lists, A and B. The challenge is to insert elements from B into A, in any order and position, to minimize the Longest Increasing Subsequence (LIS) of the combined sequence. The LIS is the largest sequence of indices in an array where each element is larger than the preceding one.

First, like described, think about the worst case and best case. Here, the worst case isn’t very relevant. However, the best case answer for this problem is that the shortest LIS of any combined sequence is equal to the LIS of A, or in other words, the answer is at least equal to the length of the LIS of A. This is because, since A is always a subsequence of the combined sequence, thus making any increasing subsequence in A available as an increasing subsequence of the final sequence as well. 

It turns out that you can always achieve the best case by inserting the elements of B into A in a certain order, and the first step to noticing this is thinking about the best case in the first place. For more details on the problem or how the solution works, feel free to check out the problem and the editorial itself. 

Furthermore, it's crucial to note that the best/worst-case scenario analysis doesn't just apply to the final solution but can also relate to the resources or steps required in solving the problem. This is exemplified in the “Closest Cow Wins” USACO Silver problem. Once again, if you wish to solve the problem by yourself, I’d advise you to skip this next part, as I will give major spoilers. 

Now, the question you should ask yourself is, what is the worst case on the number of cows Farmer John must use to get ALL patches of grass? Is it always equal to placing one cow on each patch of grass? Can we do better? 

It turns out that we need at most 2M cows, as we can place 2 cows to surround each of Farmer Nhoj’s cows, which is the main observation for the problem. This highlights how analyzing the worst-case scenario in terms of resources needed can lead to crucial breakthroughs.

In summary, the analysis of best and worst-case scenarios is not just beneficial but often essential. This technique simplifies complex challenges and is key to identifying the most efficient and effective solutions. By examining these scenarios, programmers can gain a deeper insight into the intricacies of a problem, thus guiding them towards a more targeted and successful problem-solving strategy. 

Observation Starting Points

When you begin to tackle a problem, there are several critical questions and considerations that can guide your thought process. These starting points can help you unravel the problem more efficiently.

Correctness and Solution Strategy:

• Greedy Algorithm Feasibility: Start by asking whether a greedy algorithm is applicable. What aspects of the problem make it suitable for a greedy approach? Prioritize understanding what to choose or optimize at each step. If a greedy solution isn't feasible, identify the scenarios where it fails. This understanding can guide you towards constructing a more robust solution that accounts for these failures.

• Forced and Optimal Actions: Consider if there are any forced actions or clearly optimal paths that make other options irrelevant. Identify if there are must-do steps, such as addressing a specific edge case or a particular sequence of actions that seems unavoidable.

• Dynamic Programming (For Advanced Levels): For higher difficulty levels, contemplate whether dynamic programming (DP) is suitable. Assess if the time and memory complexity are manageable for maintaining all necessary states. Determine what states are crucial for the DP solution.

• Sorting and Order of Elements: Evaluate whether sorting the elements could simplify the problem. Sometimes, the order of elements plays a crucial role, and sorting can bring clarity or make the problem more approachable.

• Graph Construction and Data Structures: Think about the possibility of constructing a graph or other data structures using the problem's elements. Organizing the components into a different structure can often provide new insights and simplify the problem.

Time Complexity and Optimization:

• Naive Solution Analysis: Identify the most naive solution first. This step provides a baseline from which you can work to optimize. Question immediately if there are apparent ways to enhance this basic solution.

• Amortization Opportunities: Look for situations where amortization might be applicable. There may be processes that seem time-consuming at first glance but are actually feasible when their cost is spread out over the course of the algorithm.

• Eliminating Time-Intensive Approaches: Recognize solutions that will definitely not run within the time constraints. Decide whether these approaches can be completely ruled out or if they can be optimized to fit within the time limits.

• Interpreting Constraints for Time Complexity: Analyze the problem's constraints to determine the viable complexity of your solution. Look for small limits or combinations of limits that suggest a certain range of complexity, typically around 1e7 to 1e8 operations.

By addressing these points when starting a problem, you can form a structured approach to making observations. This process not only aids in understanding the problem better but also in devising an efficient strategy for solving it. Keep in mind that the key to successful problem-solving in competitive programming often lies in these initial observations and the strategy that stems from them.

How to use observations effectively

Once you've made key observations in a problem, the next crucial step is leveraging these observations to guide you towards the correct solution. Observations are powerful tools, but their true value is realized only when you know how to effectively use them.

Simplifying the Problem with Observations

The primary benefit of making astute observations is their ability to strip down a problem to its essence, removing extraneous details. This process of simplification is often the turning point in problem-solving. Take, for instance, a complex-looking problem from Codeforces. At first glance, the problem might appear daunting due to its length and intricate details. However, with the pivotal observation that the optimal choice is a weight exactly equal to Polycarp’s strength, the problem transforms. It becomes a much simpler task: to find the athlete with the maximum endurance and sufficient strength. By using observations to pare down the problem, you can discard irrelevant information and focus on the crux of the challenge. Tackling this simplified version is usually far less daunting and leads to the solution more efficiently. So, after making crucial observations, consider whether the problem can be reduced to something simpler and more manageable.

Reducing the Range of Possibilities

Observations, particularly those related to forced or optimal actions, can drastically narrow down the range of possible solutions. This reduction allows for a more rapid and focused exploration of potential solutions. Refer back to the earlier example of the “Searching for Soulmates” problem. The observation made in this problem significantly reduced the possible sequences of operations, facilitating a quicker discovery of the optimal sequence. In general, once you have observations that limit the possibilities, repeat this analytical process on the reduced set of possibilities. Investigate whether there's more to deduce, further refining your approach.

Continuous Observation: The Never-Ending Cycle

Observations in problem-solving are not a one-off task but a continuous, iterative process. Many problems, particularly ad-hoc and constructive types, are almost entirely based on making a series of observations. To solve these, one must continuously observe, analyze, and deduce, building on each observation to get closer to the solution. Consider whether your initial observation can be applied to other aspects of the problem, or if it can be generalized to encompass broader scenarios. Treat each observation as a stepping stone, and view the simplified version of the problem as a new challenge. This continuous cycle of observation and analysis is crucial. It's through this iterative process that you edge closer to the right answer, regardless of the problem’s complexity.

Conclusion

Observations act as a beacon, guiding programmers through the often murky waters of competitive problem-solving. They help in simplifying problems, reducing the range of possibilities, and continuously steering thoughts towards the most effective solution. As we have discussed, whether it's deducing the implications of time complexity and constraints, exploiting the best and worst-case scenarios, or using observations to iteratively refine the problem-solving approach, each aspect underscores the same principle: keen observation is the key to unlocking the full potential of your problem-solving skills.

In conclusion, for those journeying through the competitive programming landscape, the message is clear: cultivate and refine your observational skills. Embrace the practice of looking beyond the obvious, questioning the given, and exploring the implications of every detail. As you do so, you’ll find that your ability to dissect and conquer complex problems grows stronger, making you not just a better programmer, but a masterful problem solver.

Mastering USACO Gold: Essential Strategies for Advancing to Platinum

What is USACO Gold?

The USA Computing Olympiad is a prestigious competition divided into four divisions: Bronze, Silver, Gold, and Platinum. Making it past the Gold division is the final step in the journey of reaching the Platinum division. So what makes Gold different from the previous divisions? While Silver consists of a large jump in terms of required problem solving skills and algorithmic knowledge required, the main difference with Gold-level problems is that it requires competitors to have a deep familiarity with the wide range of new concepts introduced. Problem-solving skills are nonetheless important in Gold, however the jump isn’t as big compared to Silver. If you are currently still in Silver, check out our comprehensive guide for promoting to Gold here.

Like Silver, passing Gold requires participants to dedicate a substantial amount of time to learn new algorithms and improve their problem-solving skills. In this comprehensive blog post, we aim to provide an in-depth understanding of the USACO Gold division, covering everything necessary to advance to USACO Platinum in your next competition! 

Note that the rest of the blog assumes that you have already passed Silver (or are already very familiar with the division), and thus will not cover prerequisite information from Silver. Refer to the Silver blog for more information.

Concepts You Need to Learn For USACO Gold

To begin preparing for Gold, we recommend starting by learning each concept individually before practicing on past contest problems. Jumping straight into practicing on past problems before learning the concepts can often be counter productive, because it’s very difficult to figure out these concepts on your own (especially while trying to solve a problem) and will spoil the problem for future practice. Instead, the recommended approach is to learn each topic individually, followed by practicing with a curated list of problems (e.g., the USACO Guide or Codeforces) that require that concept. 

Beyond the wide range of topics already covered in USACO Silver, USACO Gold introduces an even wider variety of new concepts.

Dynamic Programming

Dynamic Programming (DP) is by far the most important concept introduced in the Gold division. Every contest will always have at least one DP problem, so mastering DP is a must-do if you want to reach Platinum. 

Dynamic programming is an incredibly versatile technique. At its core, it consists of breaking a large problem into smaller subproblems, solving each of these subproblems just once, and storing their solutions – typically using an array. The key difference from recursion is that DP uses these stored solutions to formulate solutions to bigger problems, thus avoiding the computation of the same subproblem multiple times.

Beyond the general idea of dynamic programming, there’s a few important subcategories of dynamic programming that often show up.

Knapsack

The knapsack problem is a classic algorithmic challenge that involves selecting items with given weights and values to maximize total value without exceeding the weight capacity of the knapsack. Dynamic programming solves it by building up a table that represents the maximum value achievable for each subcapacity, from 0 up to the total capacity, considering each item at a time. Generally, you should use this technique whenever you’re trying to maximize some value by choosing items under the constraint of some other value.

Graph/Tree

DP on graphs is a very broad technique – as in the name, the technique is classified as whenever you apply dynamic programming to graphs. Typically, the DP “state” will always include a node, and any other relevant information necessary for the problem. 

This idea can also be extended to DP on grids if we represent each cell as a node and form edges between all adjacent nodes. Often, DP on grids is used to count the total number of paths from point A to B, with various constraints involved. 

DP on Ranges

The range DP technique aims to find a consecutive range of values, typically in an array, that maximize/minimize some condition. It works by combining the answers from consecutive smaller ranges to build to the answer for larger ranges, thus saving repetitive computational time. 

Digit DP

Digit DP questions are always in the form, “how many integers between A and B satisfy some property?” A and B are typically very large (around a magnitude of 10^18), so iterating through all the integers between A and B will never suffice. Digit DP incrementally builds up the solution by considering each digit position and its possible values, increasing its efficiency using memoization to avoid recalculating overlapping subproblems.

Bitmask DP

Bitmasking is the technique of taking advantage of the binary representation of numbers to represent subsets of a set. Specifically, the value of each bit in the number specifies whether a corresponding element is included in the set (1 if the element is included, and 0 if not). Applying bitmasks to DP can typically be used to efficiently count the number of permutations of a set that satisfy some property, reducing the time complexity from O(n!) down to O(2^n).

More on Graphs

Gold also introduces several new graph algorithms and techniques. Make sure that you also have a strong familiarity with silver-level graph concepts, as Gold problems often tend to involve the same concepts. 

Shortest Path Algorithms

As in the name, the shortest path problem involves finding the shortest path between two nodes in a graph. It works differently for unweighted and weighted graphs.

In an unweighted graph, the shortest path between two nodes A and B can be determined via a breadth-first traversal of the graph starting from one of the nodes, terminating when the other node is visited for the first time. 

Finding the shortest path in weighted graphs can be solved via Djikstra’s algorithm, which functions similarly to breadth-first search but instead uses a priority queue to handle the queue of nodes, rather than a simple queue. Other useful shortest path algorithms include Bellman-Ford and Floyd-Warshall. Note that these shortest path algorithms often work only if the graph does not include negative edge weights.

Union Find

The union find algorithm provides an efficient way of determining whether two nodes are in the same connected component, while supporting efficient edge insertions as well. It’s very useful whenever you need to dynamically keep track of connected components within a graph.

Topological Sort

Topological sort is an important concept for directed graphs. It can not only detect cycles within them, but it also provides a way to order the vertices in a way such that each vertex appears before any of its descendants (assuming the graph is acyclic). It’s useful whenever you need to determine ordering within some hierarchical structure (e.g. finding a milking order where some cows need to be milked before others).

Minimum Spanning Tree

The minimum spanning tree is an important concept for weighted, undirected graphs. It involves choosing edges in a connected graph such that:

1. The edges chosen connect all the vertices together (i.e., if we took out all of the edges that weren’t chosen, the graph would still be connected)

2. The sum of chosen edge weights is minimal across all spanning trees

There are two greedy algorithms for determining the MST of a weighted graph: Kruksal’s and Prim’s algorithm. Since both algorithms are rather efficient, they are generally interchangeable with one another (however they do have some tradeoffs with time and space complexity).

Point Update Range Sum

Point update range sum data structures are designed to efficiently process two types of operations on an array: updating the value at a specific index (point update) and calculating the sum of a range of elements (range sum). They’re kind of like a more powerful version of prefix sums. 

Data structures such as Binary Indexed Trees (BITs) or Segment Trees are commonly used to perform these operations in logarithmic time, making them suitable for scenarios with a combination of frequent updates and range queries.

Math

While no problem will have a solution that purely involves math, problems often require a general understanding of important math principles. 

The most important concept for Gold is combinatorics, which often works hand in hand with dynamic programming. Be sure to familiarize yourself with basic counting (permutations and combinations), binomial coefficients, recurrence relations, and the principle of inclusion-exclusion. 

Some other relevant concepts include modular arithmetic, operations with binary numbers, and number systems. Knowing these concepts will provide a sufficient math understanding to solve any Gold problem.

Resources and How to Prepare For USACO Gold

A comprehensive list of resources available can be found on the USACO Resources Page. Below, we’ve listed resources that competitors have historically found to be most useful for each stage in preparing for Gold: learning each concept, practicing each concept, and preparing for contests.

Learning Gold Concepts

If you have already passed the Silver division, you likely already have a reliable method of learning new concepts in your division. This will likely also be the best way to learn new topics in the Gold division. If you’re looking for further resources to learn concepts on your own, the rest of this section provides useful links to look into.

There are a ton of free resources available online to learn and master each concept required in USACO Gold. In particular, the USACO Guide does a great job at providing links to videos, articles, and textbooks that explain each concept in detail. 

If you want to follow a textbook specifically geared for competitive programming, a great resource is the Competitive Programmer’s Handbook by Antti Laaksonen (note: not all of the concepts covered apply to the Gold division).

Another way to learn Gold concepts is to take an online algorithms course provided by a college. Coursera hosts many good courses, most notably Algorithms Specialization by Stanford University and Algorithms Part I and II by Princeton University. While they cost money, Coursera allows you to audit them for free, or to apply for a fee waiver (it’s pretty easy to get approved as a high school student). In addition to covering relevant topics for USACO, they provide interesting projects and exercises to apply what you’ve learned, which can help place these concepts in a broader context and give you a taste for what college-level computer science classes are like. If your only goal is to prepare for USACO, however, these courses won’t be as efficient of a way to learn the concepts you need.

If you prefer learning in a more structured manner, or don’t learn on your own effectively, you may want to consider signing up for a USACO class. Classes follow a set curriculum and pace, and provide more personalized help through teachers. However, classes do cost money, and quality may vary between different organizations – do your research before signing up for one!

Practicing Gold Concepts

After learning each concept and how to implement them, the next step is to practice using that concept in past problems. Like with learning concepts, you can probably just stick with the same routine as you did in Silver. 

Often, it’s wise to organize your practice by topic – for example focusing on practicing DFS one week and then practicing two pointers another week.

The USACO Guide, once again, is an amazing resource to practice concepts once you’ve learned them. It provides a curated list of problems for each concept, enabling targeted practice once you have learned each one. 

Another useful resource for targeted practice is Codeforces, which is the biggest online site that hosts competitive programming contests. It’s also a great resource if you want to practice, but want to save past USACO problems for when you feel more comfortable. To organize your practice by concept, navigate to the problem set tab and filter the problems by a specific tag (i.e. the concept you want to practice) and difficulty range (1500 - 2200 is generally a good range for Gold). For a comprehensive guide on how to effectively use Codeforces to prepare for USACO, check out our blog here.

How to Prepare For USACO Gold

Once you feel comfortable with all the concepts tested in the Gold division, as well as how to implement them in real problems, it’s time to prepare for upcoming contests. In order to do so, do not continue practicing with concept lists! While they are great for learning concepts initially, relying on topic lists to prepare for contests can be counterproductive, as it’s much easier to solve a problem if you already know what algorithm/data structure you are supposed to use beforehand. 

The best way to prepare for upcoming contests is simply to practice on past problems! A great way to do this is to go through problems in the past contests page on USACO, start from the 2016-2017 contest season and work your way through to the more recent contests. Newer contests are typically harder than older ones, so by practicing in chronological order, you’ll gradually face harder problems as you improve through more practice. 

If you have run out of USACO problems to practice, or want to save the remaining ones for later, Codeforces is a great resource to find a ton more problems and contests. 

What to do If You’re Stuck in USACO Gold

Maybe you’ve learned all the Gold concepts and have practiced them on a bunch of problems already, or you’ve been able to solve 50% of all past Gold problems already. In these cases, would it be reasonable to expect to be promoted in the next contest? In many cases (unless you’re naturally super talented), no! Our blog post about Closing the Gap Between Expectations and Reality goes into this topic in depth. Essentially, even if you’ve solved 50% of all past Gold problems already, the problems you’ve solved are likely to be roughly the easiest 50%. However, modern contest problems are all typically on the harder end of the difficulty spectrum, meaning even though you could solve half of the Gold problems, you won’t be able to solve any problems in a contest because the level of difficulty you can handle does not encompass the contest difficulty. 

If you truly want to anticipate success for an upcoming contest, you should reach a point where you can solve more than 90% of all Gold problems. At this point, it is a lot more likely that all three contest problems will fall within the range of what you can handle — and thus you should expect success in these cases.

What if you’ve reached a point where you can solve all past Gold problems, but you still find yourself struggling in contests? This brings us to the next topic: contest strategy.

Contest Strategy For USACO Gold

Having a strong contest strategy can make or break your contest performance. In fact, during USACO camp each year, the coaches host a special lecture focused solely on developing a strong contest strategy. And every time, the campers see their scores shoot up after implementing the contest strategy.

So, what makes a good contest strategy? The key distinction between practicing on your own time and competing in contests is the time limit. While 4 or 5 hours may seem like a lot of time – it really isn’t. Thus, being able to allocate your time well is absolutely crucial for succeeding in contests. 

Riya filmed a great video detailing contest strategy in depth. The key takeaway from the video is to take practice contests with the same time constraints as a real contest. During these contests (and actual contests too), keep a contest log where you note down what you are currently working on every 15 minutes. Maintaining this log can help you identify time leaks during contests: if you notice that you’ve been working on the same problem for 1 and a half hours without significant progress, you should choose to cut your losses and move on to a different problem, coming back to the current problem later. 

After the contest is over, analyze your performance. Did you allocate too much time on a single problem? Were you too caught up in debugging because you didn’t plan out implementation well enough? Could you have solved a problem with better time management? Asking questions like these can help you identify mistakes you’ve made and learn from them, making sure that you do not repeat these mistakes in the future.

How Much You Should Practice To Pass USACO Gold

A lot of competitors often ask the question, “how many hours a week should I put into USACO to pass X division in Y time?” The answer to this question is different for everyone. It could take some competitors 2 months to pass Gold practicing 2 hours a week, and other competitors 10 months practicing 5 hours a week. 

Instead of comparing yourself to how much others practice, or frantically searching online to find a routine that worked for someone else, you need to figure out what works for you. In order to do so, create some goal in which you hope to promote by, and allocate time throughout your schedule so that you can consistently make progress every week. If you find that you’re not progressing as fast as you need to, either put more hours into practicing every week or reconsider if your goal is realistic. Another option is to find a USACO coach, which can often make your practice and improvement a lot faster, giving you time to focus on strengthening the rest of your college application.

At VPlanet, have private coaching programs starting from USACO Bronze all the way up to USACO Platinum.

Coaching from VPlanet Coding

If you’re super busy, then you need our program, so that you can advance faster and spend your time more efficiently. If you can get half your time back, then all those remaining hours can be spent on something else to make your college apps that much more competitive.

Here are 5 key benefits that we provide over other alternatives:

Comprehensive curriculum for each division

VPlanet provides dozens of hours of video content with in-depth algorithms and problem walkthroughs, covering all the knowledge a student needs to know to become successful. Additionally, our curriculum teaches the essential problem-solving skills that are required beyond the knowledge of algorithms.

Carefully curated problems

Practicing on your own can be frustrating and inefficient. We know what it’s like to spend 2 hours thinking through a problem just to give up and read a solution you can barely understand. VPlanet has handpicked 100+ problems for each division, ensuring that the problems students work on are never too easy or too hard. We guarantee that each problem has just the right level of difficulty to optimize students’ improvement trajectory. 

Daily support from coaches

If students are ever stuck or confused, VPlanet provides daily support in the form of Facebook group discussions, Q&A, and one-on-one sessions with highly-experienced coaches. These sessions maintain a very small ratio between students and coaches to ensure that everyone receives as much personalized help as possible. 

In contrast, a typical USACO class can have as many as 30 students assigned to one teacher, with only 1-2 class sessions per week to ask for help. This class environment makes it difficult to ask for help and risks leaving many students behind.

Work at your own pace

An inevitable issue with USACO classes is that they fail to account for each student’s individual skill level. This issue guarantees that either a significant number of students are falling behind in class, or the class is too slow for many high-achieving students. VPlanet overcomes this issue, enabling students to go at the pace they want with regular support from coaches.

Advance faster

We find that VPlanet students tend to advance at a much faster pace than others. Our carefully crafted curriculum and sessions with coaches provides just the right amount of content and personalized support for students to improve as fast as possible. This leaves our students with more time to focus on other activities to strengthen their college applications.

Conclusion

Mastering the USACO Gold division requires a multifaceted approach, delving into an array of advanced concepts and problem-solving strategies. This comprehensive guide serves as a roadmap for aspiring participants, emphasizing the importance of deeply understanding concepts, targeted practice, and realistic expectations. Transitioning from theoretical comprehension to practical implementation is pivotal, coupled with an emphasis on effective contest strategies to manage time and learning from mistakes. By embracing these principles, individuals can navigate the challenges of Gold, enhancing their competitive programming skills and setting a solid foundation for future success in higher USACO divisions.

A Comprehensive Guide on Using Codeforces To Practice For USACO

Codeforces is probably the single best resource for preparing for USACO outside of, of course, USACO itself. So, today, I’ll dive into how to most effectively use this resource. 

Overview

Contests and Rating System

Codeforces is centered around its contests, which are hosted on average about once or twice a week. There are 4 divisions of Codeforces contests: Divisions 1 through 4. These divisions are based on its rating system, which is an ELO rating system very similar to Chess’ FIDE ratings. 

The different titles for ratings are: 

• Newbie: 0-1200

• Pupil: 1200-1399

• Specialist: 1400-1599

• Expert: 1600-1899

• Candidate Master: 1900-2099

• Master: 2100-2299

• International Master: 2300-2399

• Grandmaster: 2400-2599

• International Grandmaster: 2600-2999

• Legendary Grandmaster: 3000+

Here are the different titles as shown on Benjamin Qi’s rating graph.

Division 4 contests are for those rated below 1400. Division 3 contests are for those rated below 1600. Division 2 contests are for those rated below 1900/2100, and division 1 contests are for those rated above 1900. 

The reason that division 2 contests have different cutoffs is because there are 2 different types of division 2 contests. The first type is a standalone division 2 contest, where there is no division 1 contest counterpart. Since there is no division 1 contest to go with this, people rated from 1900-2099 are allowed to compete. The second type consists of both a division 1 and a division 2 contest at the same time, with some of the same problems. Here, since there is a division 1 contest, people rated 1900+ must participate in division 1, while only people below 1900 can participate in division 2. 

Lastly, there is one other type of contest, which is a “global” contest, where every single person no matter the rating participates in the same contest. In these contests, to accommodate both the lower rated and higher rated participants, there are usually many problems (8-10) with a large range of difficulties.  

Within each contest, there can be anywhere from 5-10 problems. The first problem is A, the second is B, etc. In this blog, if I refer to Div2A, that means the first problem of a contest in division 2. 

When it comes to correspondence to USACO divisions, Codeforces is, overall, a bit of a different style from USACO and Olympiad problems in general, thus, there isn’t a strict 1 to 1 from Codeforces problems to USACO problems. However, if I had to give an estimate, USACO Bronze problems are around Div2B-C, Silver problems are around Div2D-E, Gold problems are around Div1B-C, and Platinum problems are around Div1C+. 

As for the rating system, I’d estimate that Bronze competitors should be a Codeforces rating of around 1000-1200, Silver competitors should be a rating of around 1200-1500, Gold Competitors should be a rating of around 1500-1800, and Platinum competitors should be 1800+. Again, Codeforces problems are a bit of a different style from USACO problems, so there are many competitors that are better at USACO but worse at Codeforces, and vice versa. So, take these estimates with a grain of salt. 

Problemset

Codeforces also has a problemset, which, like USACO, consists entirely of problems from past contests. Within this library of past contests, Codeforces has over 9000 problems! 

Each problem has a rating difficulty between 800 and 3500. In general, a contestant with a rating of “x” should be able to solve “x” rated problems at least 50% of the time in contests. 

How do the problem difficulties match up to USACO divisions? Again, Codeforces style problems are a bit different from USACO’s style, but here are a few general guidelines. 

• Beginner: 800-1000

• Bronze: 1100-1500

• Silver: 1600-2100

• Gold: 2100-2400

• Platinum: 2400+

Keep in mind that Codeforces problems are meant to be solved at a much faster pace than USACO. You tend to have 2 hours for 5-6 problems rather than 4 hours for 3 problems, which makes USACO problems for a division harder than the corresponding Codeforces problems that a contestant of that division would be able to solve. 

Problems also have tags, such as: “binary search”, “data structures”, “dfs and similar”, “graphs”, etc. Much like the USACO Guide, you can use these tags for targeted practice. 

Here is an example of a problem on the Problemset page. Under the problem name are tags such as “dp”, “greedy”, “math”, etc, and to the right, there is a number indicating difficulty.

Improving With Codeforces

Participate in Contests

Codeforces contests are an amazing way to practice contest skills, measure your progress, and keep up motivation. Division 2 contests are hosted really often, about once a week! The other 3 divisions are much less frequently hosted. Luckily, when it comes to USACO, mastering division 2 contests and being able to solve all problems in contests consistently can definitely push you to Platinum, and maybe even camp. I’d recommend competing in every single Codeforces contest that you are able to.

To check for upcoming contests, you can either go to the contests tab, or check the Codeforces calender.

Practicing Contest Skills.

Codeforces contests provide a diverse range of problems that demand creativity, a thorough understanding of algorithms, and a mastery of data structures. The real-time, high-pressure environment is perfect for cultivating your problem-solving abilities. During these timed challenges, you'll learn to quickly comprehend problem statements, devise efficient solutions, and code them accurately under time constraints. This kind of practice is essential in competitive programming, where precision and speed can make all the difference.

Furthermore, live contests enforce a level of rigor and discipline that is often not present in regular practice sessions. This aspect is crucial in preparing for high-stakes competitions like USACO.

In a typical practice environment, it's common to seek external assistance or hints when you're stuck on a problem or can't debug an error. However, in a contest setting, such luxuries are absent. If you encounter a bug in your code, the onus is on you to identify and rectify it, without the option to peek at the failing test case or seek external help. This scenario forces you to engage deeply with your code, enhancing your debugging skills and attention to detail.

Imagine spending over 1 hour trying to spot a bug in your code during a contest. This is not just a test of your technical skills, but also of your patience and perseverance. It teaches you to systematically comb through your code, develop hypotheses about potential errors, and test these hypotheses rigorously. This kind of persistence is a valuable trait in any programmer and is particularly crucial in competitive programming, where understanding and fixing your own mistakes is often the difference between success and failure.

Speed

While USACO emphasizes solving fewer, more complex problems within a generous time limit, Codeforces adopts a different approach. With typically 5-6 problems to solve in a 2-hour window, the initial problems, which are relatively simpler, test your speed and implementation skills. Although these "easier" problems might not stretch your algorithmic thinking to its limits, they are excellent for improving your coding speed and efficiency. This is crucial because in contests like USACO, quickly dispatching the simpler problems frees up valuable time for the more challenging ones, potentially impacting your overall score.

Measuring Progress

Throughout the months of April-December, USACO hosts no competitions. This also means that most competitors are improving the most during these months, and coming back stronger than ever in the December contest. However, since it is such a long period of time, it is easy to lose track of your progress during these months, and be in a spot where you aren’t sure whether you are ready for the upcoming USACO season. Codeforces contests and its rating system can help with this. 

By participating in many division 2 contests, you can get an effective measurement of your progress. For example, if you just made it to the silver division in the US Open contest in March, and you reached 1800 in rating on Codeforces, you can be pretty confident that you’ll be able to make Gold in December. 

Of course, still keep a few problems from USACO around to measure your true progress. But since USACO and Codeforces are both competitive programming, improving in Codeforces translates to improvement in USACO, and doing contests consistently can be a great measurement of your progress. 

Motivation

As highlighted in one of my other blogs about motivation, contests can significantly boost your drive to improve. The dynamic and competitive atmosphere of a live contest makes the experience more engaging compared to routine practice. Time seems to fly during these events, with two hours feeling like mere moments. The adrenaline rush and the pressure to perform can often push you to delve deeper into problem-solving, making it an effective and enjoyable form of practice.

Effectively use the Problem Set

Understanding the Problem Set Interface

Before diving into the practice methods, it's crucial to understand how to navigate the Codeforces problem set. On the problem set page, you'll notice filters on the right side, allowing you to sort problems by difficulty and tags. These filters are your gateway to customizing your practice routine.

Method 1: Blind Practice

Blind practice is about solving problems without prior hints or knowledge of the underlying concepts they test. It mimics the unpredictability of actual competitions, where you don't know what type of problem you'll encounter.

• Selecting the Difficulty: Start by using the difficulty filter. If you’re unsure about your starting level, refer to the guidelines correlating your division to a Codeforces difficulty rating. Attempt a few problems at this level. If they seem too easy or too hard, adjust the difficulty rating accordingly until you find a challenging yet solvable range.

• Avoiding Hints: For a true blind practice experience, disable the visibility of tags for unsolved problems. This option, found on the right side of the problem set page, helps avoid unintentional hints and encourages you to develop problem-solving skills from scratch.

Method 2: Targeted Practice

Targeted practice focuses on honing specific skills or concepts. It's ideal for working on your weak areas or mastering new algorithms and data structures.

• Filtering by Tags: Identify the areas you want to improve or learn. Use the tag filter to select problems related to that concept, be it dynamic programming, graph theory, or any other category.

• Balancing Difficulty: Even with tag-specific problems, maintain a balance in difficulty. If you are at the silver level, for instance, tackling a 3500-rated graph problem might be counterproductive. Choose problems that push your limits but remain within a realistic scope of solving.

For example, if you are a silver competitor wanting to practice binary search, you might filter 1800 difficulty binary search problems as shown.

A Structured Approach to Division Mastery

For those newly promoted to a division or aspiring to climb higher, here's a structured approach to use the Codeforces problem set effectively:

• Learning Phase: Begin with acquiring the necessary knowledge base. This includes algorithms, data structures, and techniques pertinent to your division level. Utilize resources like textbooks, online courses, and tutorials to build a solid foundation. The USACO guide is a great resource for learning all things necessary for a particular division.

• Blind Practice Phase: Once you're comfortable with the theoretical aspects, shift to blind practice. This phase helps you apply your knowledge in diverse situations, enhancing your adaptability and problem-solving speed.

• Targeted Practice Phase: As you approach mastery of your current division, identify areas that still pose challenges. Use targeted practice to focus on these topics, refining your skills and eliminating weaknesses.

Do Virtual Contests

Doing contests are such effective ways to improve both your problem-solving skills and your contest skills that even virtual contests are an amazing way to practice. These simulations of real contests not only boost your problem-solving and contest skills but also play a vital role in maintaining your motivation.

The Mechanics of Virtual Contests

Virtual contests on Codeforces are designed to mimic the experience of participating in a live contest. To embark on a virtual contest:

• Accessing Virtual Contests: Navigate to the contests page on Codeforces. Under each contest title, you'll find two options: 'Enter' and 'Virtual Participation'.

• Initiating a Virtual Contest: Choose 'Virtual Participation' and select a time to start. Once you begin, Codeforces replicates the conditions of a live contest. You won't have access to test cases or the ability to view other competitors' solutions during the contest.

This is what the virtual participating page will look like. Pick a time where you will be ready to start the virtual contest (most likely within the next 10 minutes), and click “virtual participation”.

Choosing the Right Virtual Contest

When it comes to selecting which virtual contest to tackle, here are some guidelines:

• Starting with Educational Rounds: For beginners and those looking to solidify their foundational knowledge, the 'Educational' rounds on Codeforces are an excellent choice. These rounds focus on fundamental algorithms and problem-solving skills, offering a comprehensive practice experience. With over 150 educational rounds available, they provide a vast resource for consistent learning and practice.

• Progressing to Division Contests: Once you've navigated through the educational rounds, or if you're looking for more diverse challenges, consider participating in Division 1 or Division 2 contests. Your choice should align with your current Codeforces rating and your USACO division. Generally, Division 2 contests are suitable for most competitors, but if you are in the USACO Platinum division, venturing into Division 1 contests can offer the advanced challenges you might be seeking.

Benefits of Virtual Contests

• Flexibility: Unlike scheduled live contests, virtual contests offer the flexibility to practice under real contest conditions at a time that suits you.

• Real-Contest Environment: By simulating the constraints and pressures of a live contest, virtual contests provide an authentic experience that sharpens your ability to perform under similar conditions in actual competitions.

• Skill Enhancement: Regular participation in virtual contests helps in improving your problem-solving speed, accuracy, and efficiency, essential traits for any competitive programmer.

• Motivation and Progress Tracking: Keeping up with regular virtual contests can be motivating, especially as you see your skills improving. They serve as a benchmark for your progress and a reminder of your growing capabilities.

Additional Codeforces Features

Gym: A Hub for Diverse Contests

The 'Gym' section on Codeforces is a treasure trove of unofficial contests. It's a space where users can engage with a wide array of competitions, ranging from renowned global challenges like the ICPC and Google Code Jam to local contests organized by educational institutions. This feature not only allows you to participate in these contests but also offers the unique opportunity to contribute by setting problems and organizing your own contests. The Gym is an excellent resource for those seeking to experience different formats and problem sets beyond the standard Codeforces contests.

Custom Invocation

Custom invocation on Codeforces is an integrated tool that functions as a versatile code runner. Accessible from the 'Problemset' tab through the 'Custom Test' option, it supports a range of programming languages. This tool is invaluable in several scenarios:

• Handling Undefined Behavior: In languages like C++, certain actions (like division by zero or integer overflow) can lead to undefined behavior, resulting in discrepancies between local and Codeforces results. The custom invocation allows you to test how Codeforces interprets your code, ensuring that your solutions are consistent with the platform's behavior.

• Alternative to Local IDEs: There are instances where your local integrated development environment (IDE) may encounter issues, such as difficulties in running code with large arrays in C++. In such cases, Codeforces' custom invocation offers a reliable alternative for running and debugging your code.

Codeforces’ built-in IDE

Blogs: A Window into the Codeforces Community

Blogs are a central feature of the Codeforces ecosystem, with the homepage showcasing a mix of contest announcements and user-generated content. These blogs serve multiple purposes:

• Learning from the Community: While personal journey blogs offer motivational insights, the true educational value lies in the detailed guides and discussions about specific algorithms. Many users post comprehensive tutorials and explanations, making these blogs a valuable learning resource.

• Engagement and Interaction: Codeforces blogs are more than just informational; they're interactive. You can share your experiences, ask questions, and engage in discussions, often receiving feedback and insights from fellow competitive programmers. This interaction fosters a sense of community and collaborative learning.

However, it’s important to approach these blogs with a mindful strategy. While they are rich in content, spending excessive time on them can divert attention from actual problem-solving practice. Use these blogs judiciously, focusing on content that directly contributes to your skill development.

Conclusion

Codeforces emerges as an essential resource for competitive programming enthusiasts, especially for those preparing for challenges like the USACO. With its diverse contests, ranging across various divisions and a rating system akin to an ELO rating, the platform offers a rigorous yet nurturing environment for sharpening coding skills. Its extensive problem set, featuring over 9000 problems with varying difficulties, facilitates both broad-based and targeted practice. Unique features like the Gym for a variety of contest experiences, custom invocation tools for code testing, and interactive blogs for community engagement further enrich the learning experience. Whether it’s maintaining momentum during the USACO off-season or enhancing problem-solving speed and accuracy, Codeforces provides invaluable tools and opportunities for growth.

Participating in both live and virtual contests on Codeforces is not just about solving problems; it’s about developing critical skills such as precision, speed, and resilience under pressure. These contests, along with the platform's comprehensive features, offer a realistic and challenging environment for progress tracking and skill enhancement. The platform serves as more than just a practice arena; it’s a community that fosters learning and improvement, catering to programmers at all levels. By fully leveraging Codeforces, from its problem sets to its community-driven features, competitive programmers can significantly boost their capabilities, preparing them for the rigors and demands of competitions like USACO.

How to Get Started with USACO With No Coding Experience

Here’s the full video where I discuss the same content in detail: How to Get Started with USACO – No Coding Experience Required!

Today, I want to discuss how to start preparing for USACO (USA Computing Olympiad) with no prior programming experience. We'll be building our coding skills from scratch, so let's dive right in.

The Importance of Coding

Before we delve into the nitty-gritty of getting started with USACO, let's briefly discuss the significance of coding. Coding, or computer programming, is the process of giving instructions to a computer to perform specific tasks. In today's digital age, coding is an incredibly valuable skill. It underlies almost every aspect of modern life, from the software that powers your smartphone to the algorithms that shape your online experience.

Furthermore, competitive programming in general has many useful applications outside of just USACO. Many classes you take in high school or college will require the knowledge of algorithms and data structures that you will learn in competitive programming. In fact, most technical interviews in the software engineering industry are algorithmic, and gaining skills in competitive programming can trivialize them. 

USACO is a prestigious competitive programming contest for students in the United States, and it's an excellent platform to hone your coding skills. The contest challenges participants with complex algorithmic problems that require logical thinking and coding expertise. But what if you have no coding experience? Don't worry; we'll guide you through the process step by step.

Choosing the Right Programming Language

Assuming you're starting from scratch, the first decision you need to make is which programming language to learn. For USACO, the two most common choices are C++ and Java.

C++ is the preferred language for most competitive programmers, including USACO participants. It's known for its speed and versatility, making it an excellent choice for algorithmic problem-solving. 

Java is another option, especially if you plan to take AP Computer Science A (APCSA), which is taught in Java. Keep in mind that while C++ is the primary language used in USACO, almost all problems can be solved using Java. In my experience, once you've learned C++, picking up Java isn't a significant challenge.

Learning the Basics

With your choice of programming language in mind, let's take the following steps to get you started:

Setting Up Your Coding Environment

The first step to being able to program at all is setting up your coding environment. You'll need a code editor and a compiler. A code editor is where you'll write your code, and the compiler is responsible for translating your code into instructions that the computer can execute.

There are different code editors to choose from, such as Visual Studio Code, Sublime Text, or CLion for C++. As for compilers, you'll need to install one that's compatible with your chosen programming language. For C++, try installing a g++ compiler. 

The setup process can be a bit tricky, especially if you're new to coding. It may involve downloading and configuring software, so be patient and persistent. You'll likely encounter some hiccups along the way, but don't be discouraged. Online resources like YouTube videos, forums like Stack Overflow, and documentation are your allies in overcoming setup challenges.

If you have friends or family members with coding experience, or are working with a tutor, don't hesitate to seek their assistance. Their guidance can significantly streamline the setup process.

Writing Your First Program: Hello, World!

The "Hello, World!" program is a classic introduction to coding. It's a simple program that prints the words "Hello, World!" on the screen. In the Python language, this is as simple as: print “Hello, World!”. Try searching for what the “Hello, World!” program would look like in your language of choice, and experiment with different print outputs. 

It may seem basic, but creating this program serves a crucial purpose: it confirms that your coding environment is correctly set up and functioning. It's your first taste of coding, and it's a milestone that shouldn't be underestimated.

External Resources

Online Tutorials and Courses

As you progress in your coding journey, consider enrolling in online tutorials and courses. It’s often really difficult to learn alone, especially when you are just starting out. Many websites offer free coding tutorials, making it easier than ever to learn. Sites like Codecademy, Coursera, edX, and Khan Academy provide valuable resources for beginners.

Additionally, if you're looking for a more structured and comprehensive learning experience, you can explore paid online courses. These often come with instructors, assignments, and a community of learners to support you.

Finding a Mentor or Tutor

If you prefer a more hands-on approach, hiring a coding tutor can be incredibly beneficial. Tutors can provide personalized guidance, answer your questions, and tailor the learning experience to your needs.

Virtual tutors are available and can be cost-effective, with hourly rates starting at around $20. However, when selecting a tutor, it's essential to consider their qualifications and reviews to ensure you're getting quality instruction.

Components of a programming language

Learning the Basics of Your Chosen Language

As you build your coding knowledge, your goal is to move beyond "Hello, World!" and tackle more complex programs. Start with small, manageable projects that apply the concepts you've learned.

For example, you can create a program that asks the user for a number and then prints double that number. This project involves taking input, performing a calculation, and displaying output. These fundamental skills will serve as building blocks for more advanced projects.

Both C++ and Java have their unique syntax and features. Understanding the fundamentals is essential. Here are some concepts we will explore:

• Variables: Learn how to declare and use variables. In C++, you'll encounter different data types like integers, strings, and more.

• Operators: Explore mathematical and logical operators like +, -, *, /. Understanding how to perform calculations and comparisons is fundamental.

• Control Structures: Learn about conditional statements and loops (for and while). These structures are the building blocks of any coding project. They enable your code to make decisions and repeat tasks.

• Input and Output: Understand how to get input from users and display output. This is crucial for interacting with your programs.

• Functions: Get familiar with functions, which allow you to organize your code into manageable blocks. Functions make your code more readable and modular.

Variables

In the world of programming, variables act as containers that store different types of information. Imagine them as labeled boxes where you can place numbers, text, or other data. Each variable has a name that you choose, which helps you access and manipulate its contents throughout your program. For instance, you can create a variable called "age" to hold someone's age, "name" to store their name, or even "is_student" to represent a yes-or-no question. Variables can be updated and changed as needed, making them versatile tools for managing data.

In programming, variables can hold various types of data, and understanding these data types is fundamental. The most common data types include integers for whole numbers, floating-point numbers for decimal values, and booleans representing true or false values. Strings are used for text and characters, while lists and arrays store collections of data. Choosing the right data type is crucial because it affects how you can manipulate and interact with the data. It's essential to be aware of these data types and their properties to effectively work with variables in programming.

Operators

Operators are special symbols or keywords used to perform operations on variables and values in programming. They allow you to perform tasks like addition, subtraction, multiplication, and comparison. For example, the addition operator (+) combines numbers, while the comparison operators (e.g., == for equality, < for less than) help you compare values and make decisions in your code. Other common operators include the assignment operator (=) for assigning values to variables and the logical operators (e.g., && for logical AND, || for logical OR) to work with boolean values. Operators are essential tools for performing calculations, making decisions, and manipulating data within your programs, allowing you to create dynamic and functional code.

Input/Output

Taking user input/output is crucial for competitive programming. In general, the problems all require you to take in an input, make some calculations, and print some output, thus, having a solid foundation on how to take input/return output is crucial. 

There are two types of input/output (IO): standard I/O, and file I/O. Standard I/O is when your program reads from/outputs into the terminal, while file I/O is when your program reads from/outputs into a file. Before December 2020, USACO required competitors to use file I/O, however, in recent years, USACO has converted to standard I/O.  

Make sure you learn how to take all data types as input! To familiarize yourself with how I/O works, try writing a program that takes a string and a number, and outputs the length of the string plus the number. 

Conditional Statements

Conditional statements are decision-making tools in programming that allow you to control the flow of your code based on specific conditions. They help your program make choices and take different paths depending on whether certain conditions are true or false. The most common conditional statement is the "if statement," which allows you to execute a block of code if a given condition is true. You can also use "else" and “else if” to specify alternative actions when the condition is false or when additional conditions need to be checked. Conditional statements enable you to create dynamic and responsive programs by guiding the program's logic based on the values and conditions you specify, making them a fundamental concept in programming.

As an exercise, you can write a program that asks the user for a number and tells them whether it's even or odd. This involves using if-else statements. Note that for this exercise and some of the following ones, you will need to learn the modulo (%) operator, which returns the remainder of the division of two integers. 

Exploring Loops

Loops are essential constructs in programming that allow you to repeat a block of code multiple times. They enable automation and save you from writing the same code over and over. There are two main types of loops: "for" loops and "while" loops. "For" loops are used when you know in advance how many times you want to repeat a task, while "while" loops are used when you want to repeat a task as long as a specific condition remains true. Loops are valuable for tasks like iterating through lists, processing data, and performing repetitive operations. They are powerful tools for making your code more efficient and concise by automating repetitive tasks. 

To get a grasp of for loops, try solving problems that require you to print all the numbers between 1 and 100 that are multiples of 3 but not multiples of 5. It's a simple yet effective exercise to familiarize yourself with loop structures.

Arrays and Lists

Moving forward, you'll want to start learning about data structures. The most basic data structures are arrays and lists, which allow you to store multiple pieces of data in a single variable.

The general difference between arrays and lists is that arrays generally have a fixed size that must be decided as soon as it is created, while lists have a dynamic size, which means that you can continuously add elements to them, and they will continuously expand. In both Java and C++, arrays are declared with square brackets []. In C++, lists are known as vectors, and in Java, you can use ArrayList.

To practice, create a program that stores a list of numbers and computes their sum and average. This project will enhance your understanding of arrays or lists and further develop your coding skills.

Functions and Modular Programming

Functions are like building blocks of your code. They help you break down complex problems into smaller, manageable pieces. Functions take in a list of parameters, and return some kind of value. Think back to algebra, where functions were things like “f(x) = x^2”. In programming, functions are the exact same! Here, “f” is the function name, “x” is the parameter, and “x^2” is the return value. This would represent a function that takes in a number, and returns that number squared. As you continue learning, explore the use of functions to create modular code.

A simple exercise to familiarize yourself with functions is to create a function that takes in two numbers as a parameter, and returns the maximum of the two numbers. For an additional challenge, try writing a function that returns the factorial of a number (hint: you can call the function inside itself!). These exercises will teach you how to define your own functions, pass arguments, and return values.

Debugging

As you start working on more substantial projects, you'll inevitably run into errors in your code. Debugging is a crucial skill for any programmer. Learn how to identify and fix common programming errors, such as syntax errors, logical errors, and runtime errors.

Utilize debugging tools provided by your code editor and compiler. Understanding how to troubleshoot issues in your code is an essential part of becoming a proficient coder. For a tutorial on how to use a debugger, check out this video. 

Practicing on Codeforces

USACO places a strong emphasis on problem-solving and algorithmic thinking. To prepare effectively, you'll need to practice solving problems that require creative thinking and efficient algorithms.

Websites like LeetCode, AtCoder, and HackerRank offer a plethora of coding challenges that can help you sharpen your problem-solving skills. An especially popular choice is Codeforces, which stands out due to its large library of thousands of amazing problems.

Codeforces hosts numerous coding contests and provides a vast problem set for practice. To get started, create a Codeforces account, and go to the “Problemset” tab. Like USACO, Codeforces allows you to submit your solutions and provides instant feedback. This means you can test your code against various test cases and receive immediate results, and is an excellent way to assess your progress and refine your problem-solving skills.

Problems on Codeforces are categorized by difficulty ranging from 800 to 3500, and you can filter them on the right side to find problems suitable for your skill level. To start, try out some problems that have a difficulty of 800. When you are able to solve 800-rated problems without much of a challenge, move up to 900 difficulty problems, then 1000, then 1100, then 1200, etc. 

Remember that consistent practice and a willingness to learn from both successes and failures are key to your growth as a competitive programmer. So, don't shy away from tackling challenging problems and pushing your coding skills to the next level. 

Practicing USACO problems

Registering for USACO

Once you've acquired a solid foundation in coding and problem-solving and are able to solve Codeforces problems of difficulty 1000-1200, it's time to start practicing on USACO. To register, visit the USACO website, create an account, and go to the “contests” tab. 

Here, you can access a wealth of contest problems from the past few years of all divisions. 

Problem difficulties

USACO is divided into four levels: Bronze, Silver, Gold, and Platinum. Beginners typically start with the Bronze level, which is designed for those new to competitive programming. The Bronze division problems are relatively easier and serve as a great starting point.

Within each contest, there are 3 problems, which tend to have an “easy”, “medium”, and “hard” problem, which are not necessarily problems #1, #2, then #3. You can get a sense of which is which by checking out the results of that contest, and seeing which problem was solved by the most people. However, note that not all contests follow this pattern. 

Also note that older problems tend to be easier; the problems from contests in 2015-2017 tend to be a lot easier than the problems from 2017 to now.  However, this is not true for pre-2015 USACO. Before 2015, there were only 3 divisions: bronze, silver, and gold. This causes the problems in each division to be generally harder than the problems from contests after 2015, so keep this in mind when choosing where to start. 

When getting started, look for the easier bronze problems. As you improve at problem-solving, you can take on some of the harder bronze problems, and eventually, you can move on to silver. 

Implementing Solutions

One thing I want to emphasize is to pay attention to your code length. For bronze problems and easier Codeforces problems, your implementations should be around 20-40 lines. Longer implementations take much longer to code and debug, which can drastically reduce your time for other problems in a contest. 

Thus, if your implementations are consistently 200 lines or more, I’d suggest taking 20 minutes before you start coding to think about what your code will look like and plan out the structure. This will save a lot of time, as 20 minutes is preferable to the hours it can take to debug a long piece of code.  

Analyzing and Learning

After each failed problem, take the time to analyze your solutions and understand the editorial solutions provided by USACO. This is where the real learning happens.

Reflect on your approach to each problem and consider more efficient solutions. Learning from your mistakes and studying the solutions of experienced participants will help you grow as a coder and problem solver.

Conclusion

In conclusion, while starting from scratch with no coding experience may seem daunting, it's entirely possible to prepare for USACO with dedication and hard work. The key is to start small, build a strong foundation, and gradually progress through the levels. Remember that every coder, even the most seasoned ones, began as beginners.

USACO isn't just about winning; it's about the journey of learning, problem-solving, and growing as a coder. Along the way, you'll develop skills that extend beyond coding and serve you well in various aspects of life. So, whether you're aiming for the USACO championships or simply want to enhance your coding abilities, the path is clear: start today, stay persistent, and embrace the adventure of coding.

I hope you found this guide helpful, and I wish you the best of luck on your USACO journey. If you have any questions or need further assistance, please don't hesitate to ask. Thanks for watching, and happy coding!

How to Find Time for USACO With a Busy High School Schedule

Here’s the full video where I discuss the same content in detail: Finding Time For USACO With A Busy High School Schedule

Most high schoolers preparing for USACO also have a ton of other commitments – whether that be juggling multiple AP classes, clubs, or other extracurricular activities. As a result, it might feel overwhelming to also have to find time to practice USACO on top of an already busy schedule. Hi, I’m Riya, and in this blog I wanted to share everything that I did to practice for USACO on top of everything else, eventually qualifying for USACO camp three times and getting into MIT.

Finding Quality Practice Time

When preparing for the USACO, emphasis should always be placed on quality rather than quantity in practice.

As a junior managing five AP classes, I often returned home after an exhausting eight-hour school day, attempting to practice for the USACO in those limited hours after school. Unfortunately, I discovered that despite spending a considerable amount of daily time practicing, my progress remained limited. Moreover, I encountered challenges in solving problems that I could have typically handled at other times.

Conversely, during periods when I wasn't fatigued from school and possessed a strong mental focus, my progress was significantly more substantial, achieved with minimal time investment. It is crucial to locate moments during the week when mental energy and capacity align to practice the USACO most effectively. So, where can this time be found?

Undoubtedly, practicing immediately after school, when mentally drained from academic classes and extracurricular commitments, is not the optimal period. Instead, weekends present an ideal window for focused USACO preparation, devoid of academic or club obligations. If weekend activities, such as volunteering, persist, consider relocating them to weekdays. Often, these activities demand less mental bandwidth, making after-school hours more conducive for these tasks rather than USACO practice.

Allocating Morning Time to USACO

If, after moving around your extracurriculars, you still find that you don’t have much time to practice on the weekends (or there’s no way to move your extracurriculars to the weekdays), consider allocating one or two hours in the morning to USACO. 

Personally, I was able to add morning practice into my routine by sleeping earlier every day and waking up a few hours before school started. This way, I could prepare in the mornings when I was focused and high-energy, rather than after class when I was exhausted. I could go to school without maximum focus or mental energy, but I couldn’t do the same for USACO. 

Now, it’s important that you’re getting enough sleep if you want to prepare in the mornings. If you’re not sleeping a full 8-9 hours each night, your focus and mental bandwidth will inevitably be lower. If you do not like sleeping early, another way of allocating time is to take a nap after school. Then, once you wake up, you’ll have a clear mind and mental energy to practice for USACO.

Misconceptions

Don’t interpret this blog post as saying that you should only practice for USACO when you’re in perfect mental condition! There will be times where you’ll inevitably feel drained during the time in which you’re supposed to practice for USACO, and that’s okay. The message I’m trying to get across is that you should aim to maximize the amount of time you practice USACO when you’re not feeling drained. 

If you’re having a bad day or not feeling fully energetic, still put in time to practice and solve a couple problems. In the end, keeping a consistent schedule is more important than making sure that you’re only practicing at maximum mental capacity.

The message that I do want to get across is that if you find that you’re consistently feeling tired whenever you’re practicing, something needs to change.

Maximizing Quality and Quantity

While it’s definitely true that quality practice is more important than quantity, you’ll always be better off maximizing both quality and quantity. The important thing to note here is to learn to say no to things. If, for example, you have a leadership opportunity at some extracurricular organization, but you don’t think it would be a significant addition to your college application, then it’s not worth taking. You could spend all the extra time that you just freed up practicing for USACO, or strengthening other activities.

Personally, I was president of my computer science club in high school. I was also participating in a Girls Who Code club, where I was also voted to be president. Instead of taking the position, I ended up swapping positions with the vice president. I figured that being president of two of these clubs would not significantly boost my application over just being president of one of the clubs, and thus stepping down from one of the roles would free up a lot of time for USACO practice. 

In sum, do not be afraid to say no to commitments that don’t get you where you need to be (this is just good life advice in general too).

Conclusion

Overall, effective USACO preparation within a busy high school schedule demands a focus on quality practice. Adapting practice times to weekends and early mornings while balancing mental stamina proved instrumental. Adjusting commitments underscored the essence of focused, quality practice alongside mindful decisions. It's a challenging yet rewarding journey, one that emphasizes the importance of strategic time management and commitment choices in achieving success amidst a packed schedule.

How do USACO and Competitive Programming Fit Into Your Journey?

In the fast-paced world of technology and innovation, competitive programming stands as a beacon for students aiming to carve out a remarkable niche in their academic and professional journeys. Particularly in the context of the United States of America Computing Olympiad (USACO), it offers a unique blend of challenges and opportunities. As a multifaceted arena, competitive programming extends beyond just a test of coding skills; it's a gateway to enhancing one's educational and career prospects. This blog aims to delve into how USACO and competitive programming can be pivotal in shaping your journey, starting from the bustling halls of high school to the competitive corridors of the job market.

Embarking on this exploration, we will first examine how competitive programming can be a significant advantage in college admissions. It's not just about the algorithms and data structures; it's about demonstrating to colleges your ability to think critically and solve complex problems. For high school students juggling academics, extracurricular activities, and perhaps even part-time jobs, fitting competitive programming into an already packed schedule might seem daunting. However, we will provide insights and strategies to integrate this valuable pursuit seamlessly into your daily life. Additionally, we will highlight the tangible benefits that competitive programming offers in your job search, underscoring how it can be a game-changer in securing your dream job. Lastly, we will touch upon the overarching theme of how competitive programming inherently enhances problem-solving skills, an attribute that transcends the confines of coding and becomes a lifelong asset. Join us as we unravel these facets, illustrating how competitive programming is not just an activity, but a journey that shapes your intellectual and professional identity.

Middle/Early High School

Middle and high school years are a time of exploration and discovery, where students begin to shape their interests and talents. It's during this phase that the world of competitive programming can offer a stimulating and enriching experience. If you're a middle schooler or in the early years of high school, this is the perfect time to dive into the exciting realm of competitive programming. As you enjoy your childhood, which indeed should be full of fun and learning, integrating competitive programming into your activities can set a strong foundation for your future endeavors.

Competitive programming is not just another extracurricular; it's a journey into the world of logic, creativity, and problem-solving. Unlike traditional STEM subjects, which often have straightforward, objective answers, computer science and competitive programming offer a canvas for creativity. Here, you're not just learning to code; you're learning to think in innovative ways, to approach problems from different angles, and to find solutions that are as unique as they are effective. This aspect of competitive programming makes it not only intellectually stimulating but also incredibly fun. It challenges the mind while allowing for a personal touch in every solution you devise.

Moreover, the scope for growth in competitive programming is boundless. With various levels and divisions in competitions like USACO, you can continuously measure and challenge your progress. But the journey doesn't end at reaching the top in national ranks. The international arena is vast, with thousands of like-minded peers to compete against and learn from. This endless horizon of improvement sets competitive programming apart from more finite academic achievements like SAT scores or school grades. It's a field where the learning never stops, and the sky's the limit.

Starting early in competitive programming or USACO is an investment in your future. It's not just about coding; it's about developing a mindset that values continuous learning, problem-solving, and creative thinking. These are skills that will serve you well, no matter what path you choose in life. The benefits of competitive programming are manifold, affecting both your short-term academic achievements and your long-term career prospects.

If this is your first encounter with competitive programming, let this blog be the nudge you need to get started. And don't worry if you're unsure where to begin. We have resources and guides, including a blog on how to start your journey in competitive programming. Take the first step into this fascinating world, and you might just find a passion that shapes your future in ways you never imagined. So, grab your computer, fire up your curiosity, and embark on an adventure that promises to be as rewarding as it is challenging. Happy coding!

High School

As you navigate through the later years of high school, the focus inevitably shifts towards college applications. This period is crucial for building a strong profile that showcases your talents and interests. Competitive programming, especially through platforms like the United States of America Computing Olympiad (USACO), emerges as an exceptional activity to include in your college applications. Let's delve deeper into why competitive programming can be a significant asset in your college admissions journey.

Firstly, USACO offers a clear framework for demonstrating measurable progress in programming. With its tiered system of Bronze, Silver, Gold, and Platinum divisions, each level represents a step up in complexity and skill. Achieving the higher divisions, particularly Gold and Platinum, stands as a testament to your dedication and expertise in programming. Colleges and universities, well-versed in the rigors of USACO, understand the significance of these achievements. When admissions officers see "USACO Platinum" on your application, it speaks volumes about your proficiency in programming and your ability to tackle complex problems. This recognition is invaluable in an increasingly competitive academic landscape.

The limitless potential for growth and recognition in USACO sets it apart from other standardized measures like the SAT. In competitive programming, there's no upper limit to what you can achieve. Reaching the Platinum division is just the beginning. The journey can lead you to become a USACO finalist, an invitation to the prestigious USACO Camp, reserved for the top contenders in the Platinum division. This achievement alone can significantly bolster your college application. But the opportunities don't stop there. If you excel further, becoming a repeat finalist or even qualifying for the International Olympiad in Informatics (IOI) team, you could be in contention for an IOI medal. Such accolades are often viewed by top colleges as indicators of exceptional talent and potential, making them near-guarantees for admission to prestigious institutions.

Additionally, the skills honed through competitive programming have a broad application. Many students who excel in USACO also find success in other Olympiad competitions, such as the USA Mathematical Olympiad (USAMO) or the USA Physics Olympiad (USAPHO). This crossover success is due to the universal problem-solving skills developed through competitive programming. However, it’s important to recognize that while the fundamental skills of problem-solving are transferable, each discipline has its unique aspects. Excelling in competitive programming provides a strong foundation, but mastering other subjects requires dedicated effort and understanding of their specific nuances.

Participation in USACO and competitive programming presents a multifaceted opportunity for aspiring college students. It not only showcases your technical skills but also your commitment to learning and excellence. The measurable progression, the absence of an upper limit in achievements, and the transferable problem-solving skills make competitive programming a powerful component of your college application. Engaging in this challenging yet rewarding field could be a pivotal step in securing admission to a prestigious college and setting the stage for a successful academic and professional career.

Fitting USACO and Competitive Programming Into A Busy High School Schedule

Now that we have established USACO’s potential as a boost to your college applications, how can we fit it into your schedule? Integrating USACO and competitive programming into a busy high school schedule can be a daunting task, but with the right approach, it's entirely feasible. As we've highlighted, the benefits of excelling in USACO for college applications are significant. However, balancing this with academics, extracurriculars, and personal life requires strategic planning and smart time management. Let's expand on how you can effectively incorporate USACO into your bustling high school life.

Prioritizing USACO

Achieving high ranks in USACO, such as reaching the Platinum division or getting selected for USACO Camp, can significantly elevate your college application. These accomplishments often carry more weight than standard achievements like club leadership positions or high school ranks, which are more common and less distinctive. Therefore, it's advisable to prioritize competitive programming, especially if your goal is to optimize your college applications. That said, it's important to maintain a balance. If you have a deep passion for other activities, don't sideline them entirely. The key is to find a healthy equilibrium where you can pursue competitive programming without sacrificing other interests that are important to you.

Practicing Optimally

Effective practice is crucial, given the limited time you might have for competitive programming. It's essential to recognize that quality trumps quantity. Practicing while exhausted, such as immediately after a long day at school, might not be as fruitful. Instead, identify times when you are most alert and focused. This could be early in the morning, during a quiet evening, or even during weekends. Allocate more routine, less mentally taxing tasks – like certain homework assignments or organizational tasks – for times when you're feeling less energized. This strategic distribution of tasks ensures that your competitive programming practice is both efficient and effective.

Integrating Problem-Solving into Daily Life

One effective technique used by top competitors is to integrate problem-solving into their daily routines. This doesn't mean spending every waking hour coding. Instead, it's about keeping your mind actively engaged with programming problems throughout the day. For instance, you can start your day by reviewing a few problems. As you go through your school day, during breaks or less intensive classes, mull over these problems. This constant engagement helps in developing solutions subconsciously. By the time you sit down to code, you'll have a clearer idea of how to approach the problem, making your practice sessions more productive.

Creating a Structured Schedule

Having a structured schedule can make a world of difference. Dedicate specific time blocks each week solely to USACO practice. Treat these blocks like any other important commitment – no distractions, no excuses. Consistency is key here. Even if it's just an hour or two each week, regular practice can lead to significant improvements over time.

Leveraging Resources Efficiently

Lastly, make use of available resources to maximize your learning. This includes online forums, coding platforms, and educational materials specifically designed for USACO. Joining a community of fellow competitors can also be beneficial, as it allows for the exchange of ideas, strategies, and motivation.

In conclusion, fitting USACO into a busy high school schedule is all about strategic prioritization, effective time management, and consistent practice. By integrating problem-solving into your daily life, practicing optimally, and utilizing resources wisely, you can make significant strides in competitive programming while balancing your academic and personal commitments. Remember, the journey through USACO is not just about excelling in competitions; it's about developing critical thinking skills, resilience, and a problem-solving mindset that will benefit you in all areas of life.

Post-High School Benefits of Competitive Programming

Competitive programming, particularly experiences gained through platforms like USACO, extends its benefits far beyond high school and into college and professional life. It's a misconception to think that the skills developed through these competitions become redundant post-college. On the contrary, they often serve as a robust foundation for future successes, especially in technology and related fields. Let's explore how the skills honed through competitive programming can be advantageous in college and beyond.

Interviewing Skills

One of the most immediate benefits of competitive programming in a post-high school scenario is its relevance to job interviews, particularly in fields like software engineering. In our technology-driven world, the demand for software engineers is constantly growing. The nature of job interviews in this sector often leans heavily on algorithmic and problem-solving skills. Competitive programmers, especially those who have excelled in USACO, tend to find these algorithm-based interview questions more approachable and sometimes even trivial. While software engineering interviews can encompass a broader range of topics, the edge provided by a background in competitive programming is undeniable.

Additionally, competitive programming skills are increasingly valued in the finance industry, especially in roles like quantitative developers, traders, and researchers. These positions often require strong algorithmic thinking and problem-solving abilities, skills that are rigorously developed through competitive programming.

ICPC: The Collegiate Arena

The International Collegiate Programming Contest (ICPC) is a natural progression for competitive programmers entering college. Often compared to USACO or IOI, ICPC presents a unique challenge: it's a team-based competition. Competing in teams of three, participants tackle problems collaboratively, representing their colleges against teams from across the globe. The dynamics of team competition add a new layer of complexity and learning opportunity, enhancing not just your coding skills but also your ability to work effectively with others.

Becoming an ICPC world champion is a coveted achievement in the competitive programming community, a testament to one's coding prowess and teamwork skills. Participation in ICPC not only continues the competitive programming journey but also enhances your college experience, offering opportunities for networking, collaboration, and significant personal and professional growth.

Continuous Learning and Challenges

Competitive programming in college isn't just about maintaining skills; it's about continuous learning and tackling new challenges. The problems encountered in collegiate-level competitions are often more complex and require deeper understanding and creativity. This continuous engagement with challenging problems ensures that your problem-solving skills remain sharp and evolve.

In summary, the journey through competitive programming offers long-term benefits that extend well into your college years and professional life. The skills developed through these competitions are highly applicable and sought after in various fields, particularly in technology and finance. Moreover, platforms like ICPC provide a continuation of this journey in college, offering new challenges and opportunities for growth. Far from becoming redundant, the skills and experiences from competitive programming become foundational elements of your academic and professional success. Whether it's acing job interviews, excelling in team competitions, or continuously pushing the boundaries of your problem-solving abilities, competitive programming sets you up for a lifetime of learning and achievement

The Overall Benefits of Problem-Solving Skills

The problem-solving skills honed through competitive programming are indeed far-reaching, extending well beyond the realms of coding and academia. These skills are adaptable and can be applied in a myriad of situations in both personal and professional life. Let’s delve deeper into how these skills, cultivated in the competitive programming environment, can be beneficial across various domains.

Transferring Skills to Other Academic Disciplines

Competitive programming primarily revolves around breaking down complex problems into manageable parts and finding efficient solutions. This approach is not exclusive to programming; it's a universal skill applicable to a wide range of academic subjects. For instance, in mathematics and physics, problem-solving involves understanding concepts, applying them creatively, and thinking logically - skills that are directly transferable from competitive programming. Once you've mastered these problem-solving techniques, your ability to grasp and excel in other subjects that demand similar skills significantly improves. It's not just about learning the content; it's about applying a problem-solving mindset that can transform the way you approach any academic challenge.

Application in Diverse Professional Scenarios

In the workplace, regardless of your field, the ability to problem-solve is invaluable. Whether you’re conducting research, involved in strategic planning, or making investment decisions, the ability to analyze situations, think critically, and devise effective solutions is crucial. For example, in research, identifying the right approach to a problem, anticipating potential issues, and finding solutions can be the difference between success and failure. In the world of investing, being able to quickly assess risks, understand market trends, and make informed decisions is essential – skills that are all enhanced by a strong foundation in problem-solving.

Everyday Life Decisions

Beyond academics and professional life, problem-solving skills are also beneficial in everyday decision-making. Simple choices, like whether to order food or cook at home, can be approached with the same logical framework used in competitive programming. By assessing the situation, considering various factors, and weighing the pros and cons, you can make more informed and rational decisions in your daily life. This ability to think critically and solve problems can lead to better choices and, consequently, a more organized and efficient lifestyle.

Developing a Problem-Solving Mindset

At the core of these benefits is the development of a problem-solving mindset. This mindset is about more than just finding answers; it’s about being curious, persistent, and creative. It involves looking at problems from different perspectives, thinking outside the box, and being resilient in the face of challenges. These attributes are beneficial not just in specific tasks or subjects but in how you approach life in general.

The problem-solving skills developed through competitive programming are multifaceted and versatile. They enhance your abilities in other academic disciplines, equip you with valuable tools for a wide range of professional scenarios, and even aid in making everyday decisions more effectively. Above all, they foster a problem-solving mindset that can lead to personal growth, success, and a more fulfilling life. Whether in a coding competition, a classroom, the workplace, or the myriad decisions of daily life, these skills are a powerful asset, shaping not just what you do, but how you think and approach the world around you.

Conclusion

As we conclude this exploration into the world of USACO and competitive programming, it’s clear that these arenas are much more than platforms for technical skill development. They are incubators for a mindset that is analytical, creative, and relentlessly problem-solving. From middle school hallways to college campuses, and eventually into the diverse paths of professional life, the journey through competitive programming equips individuals with a toolkit of skills that are universally applicable and highly valued.

The journey through USACO and competitive programming is an investment in a future where technology and innovation continue to shape our world. By cultivating a robust set of problem-solving skills, you prepare not just for a career in software engineering or a related field, but for a lifetime of thoughtful decision-making, effective collaboration, and continuous learning. These skills transcend the immediate challenges of programming competitions and become integral to how you approach challenges, big and small, in everyday life.

As you step forward, remember that competitive programming is more than a line on your resume; it is a testament to your ability to think, adapt, and excel. Whether you're a student just starting out or a professional reflecting on your educational journey, the lessons learned through competitive programming are invaluable. They teach resilience, foster creativity, and instill a problem-solving spirit that will guide you through the myriad challenges and opportunities life presents. So, embrace these experiences, cherish the skills you develop, and look forward to a future enriched by the invaluable lessons learned through competitive programming.

How to Practice Effectively for USACO – A Collection of Proven Strategies

Finding Time For USACO With A Busy High School Schedule

Here’s the full video where I discuss the same content in detail: Finding Time For USACO With A Busy High School Schedule

Most high schoolers preparing for USACO also have a ton of other commitments – whether that be juggling multiple AP classes, clubs, or other extracurricular activities. As a result, it might feel overwhelming to also have to find time to practice USACO on top of an already busy schedule. Hi, I’m Riya, and in this blog I wanted to share everything that I did to practice for USACO on top of everything else, eventually qualifying for USACO camp three times and getting into MIT.

Finding Quality Practice Time

When preparing for the USACO, emphasis should always be placed on quality rather than quantity in practice.

As a high school junior managing five AP classes, I often returned home after an exhausting eight-hour school day, attempting to practice for the USACO in those limited hours after school. Unfortunately, I discovered that despite spending a considerable amount of daily time practicing, my progress remained limited. Moreover, I encountered challenges in solving problems that I could have typically handled at other times.

On the flip side, I found that my progress was much faster during times when I was not exhausted from school and had a strong mental focus, achieving more with less time. Identifying times when your mental energy and capacity are at their peak is essential for the most effective USACO practice. So, how do you find these opportune moments?

Undoubtedly, practicing immediately after school, when mentally drained from academic classes and extracurricular commitments, is not the optimal period. Instead, weekends present an ideal window for focused USACO preparation, devoid of academic or club obligations. If weekend activities, such as volunteering, persist, consider relocating them to weekdays. Often, these activities demand less mental bandwidth, making after-school hours more conducive for these tasks rather than USACO practice.

Allocating Morning Time to USACO

If, after moving around your extracurriculars, you still find that you don’t have much time to practice on the weekends (or there’s no way to move your extracurriculars to the weekdays), consider allocating one or two hours in the morning to USACO. 

Personally, I was able to add morning practice into my routine by sleeping earlier every day and waking up a few hours before school started. This way, I could prepare when I was focused and high-energy, rather than after class when I was exhausted. I could go to school without maximum focus or mental energy, but I couldn’t do the same for USACO. 

Now, it’s important that you’re getting enough sleep if you want to prepare in the mornings. Without the recommended 8-9 hours of sleep each night, your concentration and cognitive capacity will naturally diminish. If you do not like sleeping early, another way of allocating time is to take a nap after school. Then, once you wake up, you’ll have a clear mind and mental energy to practice for USACO.

Misconceptions

Don’t interpret this blog post as saying that you should only practice for USACO when you’re in perfect mental condition! There will be times where you’ll inevitably feel drained during the period in which you’re supposed to practice for USACO, and that’s okay. The message I’m trying to get across is that you should aim to maximize the amount of time you practice USACO when you’re not feeling drained. 

If you’re having a bad day or not feeling fully energetic, still put in time to practice and solve a couple problems. In the end, keeping a consistent schedule is more important than making sure that you’re only practicing at maximum mental capacity.

However, if you find that you’re consistently feeling tired whenever you’re practicing, something needs to change.

Maximizing Quality and Quantity

While it’s definitely true that quality practice is more important than quantity, you’ll always be better off maximizing both quality and quantity. The important thing to note here is to learn to say no to things. If, for example, you have a leadership opportunity at some extracurricular organization, but you don’t think it would be a significant addition to your college application, then it’s not worth taking. You could spend all the extra time that you just freed up practicing for USACO, or strengthening other activities.

Personally, I was president of my computer science club in high school. I was also participating in a Girls Who Code club, where I was also voted to be president. Instead of taking the position, I ended up swapping positions with the vice president. I figured that being president of two of these clubs would not significantly boost my application over just being president of one of the clubs, and thus stepping down from one of the roles would free up a lot of time for USACO practice. 

In sum, do not be afraid to say no to commitments that don’t get you where you need to be (this is just good life advice in general too).

How to Practice Effectively

Beyond just finding effective times to practice, it’s also crucial to be practicing the right things – even if you are in peak mental condition, your efforts will be absolutely useless if you’re spending your time working on things that are irrelevant to your division. This brings me to the next topic I wanted to talk about, which I also happened to film a video about a while back: Why People Who Learn Lots of Algorithms for USACO Fail. The video features Yibo, who is a coach at VPlanet and a former USACO Finalist.

As mentioned in the intro, a big part of practicing is deciding what to practice and what not to practice. First and foremost, it’s important to know when you should learn a new topic that you come across.

When to Learn a New Topic

Generally, it is a good idea to learn a new topic whenever you come across a problem you cannot solve, and when you read the solution, it requires a specific concept that you do not already know. It’s very possible that such a concept could appear in the future, especially if the problem is from USACO and in your division. You should definitely look into the concept if you come across it multiple times.

If you are practicing with Codeforces problems, then this logic may not apply. Specifically, if you are practicing problems at a difficulty way above your division, there will likely be no reason to learn the advanced topic tested in the problem. For example, there would be no reason to learn segment trees as a Bronze competitor just because you ran across it in a problem rated 1800. As a general rule of thumb, don’t worry about learning concepts for problems that you encounter that are more than 1000 above your rating. In a Codeforces contest, go at most two problems beyond the problems you were able to solve.

Recently, the Silver and Gold divisions have seen a lot of harder algorithms and data structures not typically expected in the division. For instance, Silver contests have seen problems requiring the meet in the middle technique. Despite this, however, it’s generally still always possible to promote in such a contest just using the main algorithms and data structures in the division. Even if a contest problem requires some advanced concept, the cutoffs will almost always be lenient enough such that getting the first few test cases through a partial solution is sufficient to promote (given that you fully solve the other two problems). Plus, there’s really no way to prepare for an advanced topic showing up, because there are dozens of niche topics that could pop up. Thus, even with these advanced topics occasionally showing up, the expected value of learning niche topics beyond your division still isn’t high enough to be worth spending your time on.

What to do After Learning Every Concept

The hardest part about practicing for a division is the stage when you feel like you’ve finished learning all the topics, but still get stuck on a lot of problems. Reading the solution, you technically have the knowledge to solve it – but you still weren’t able to. The reason why this often happens is even though you are familiar with the topic, you have not yet learned how to apply that topic. Often, problems will introduce a lot of twists and abstractions where it is not at all obvious that you are even supposed to use the intended topic in the first place.

Getting past this stage really just requires you to improve your problem solving skills, and the best (and really only) way to improve these skills is to practice a lot of problems. Now when it comes to practice, quality is still far more important than quantity. In other words, spending a few minutes reading a question, barely thinking about it, and reading the solution after giving up will not get you anywhere, even if you manage to get through a bunch of problems really quickly. Sure, you now know what topic is used for each question, but you have never developed any actual problem solving skills to determine the topic and how to apply it for problems you have never seen before.

The most important way to ensure you are getting in high quality practice is to be hands-on with problems. Do not just sit there staring at the problem and hope that a solution will magically come to you! Draw out examples on paper, try different test cases, and look for patterns to develop your solution. When it comes to creating your own different test cases, try to make each of your test cases unique in some way – make sure you’re covering edge cases and extremes, as well as more average cases. Additionally, when you’re testing your solution idea against your test cases, try to figure out what specifically about the test cases make the solution work, and think about if there are any test cases that do not satisfy that. 

How Long Should You Work on a Problem Before Giving Up?

While you definitely should never give up on any problem too quickly, spending too much time trying to solve a problem can be just as inefficient. So, when is the right time to call it quits and read the solution?

Generally, it’s a good idea to keep trying as long as you feel like you’re making progress. But at some point, if you get stuck and don’t think you’ve made any progress for 15-30 minutes, this is usually the point where you should get some external help (reading the solution, getting a hint, etc.).

Advice for Platinum Competitors

While it’s best to learn all the topics relevant to your division in Silver and Gold, this isn’t necessarily the case. There are a huge variety of topics that could pop up in a Platinum contest, with some showing up only once every few years. As a result, learning every single topic that could ever show up will quickly yield diminishing returns. 

A better approach is to focus on practicing common topics like dynamic programming and graphs, as these problems always show up at least once in every contest. Mastering graphs would yield a much better expected return than mastering a concept that only appeared once in a contest 5 years ago. Thus, the recommended approach is to learn all the important algorithms and data structures in the division, but don’t bother with those that show up once in a blue moon.

Another difference between the Platinum division and the Silver and Gold divisions is the wide range of problem difficulty. Some Platinum problems will be pretty easy (maybe hard Gold level), but others will be so hard that even IOI competitors failed to fully solve them. As a result, don’t expect to solve every problem you encounter in practice – instead, focus on the easy ones first and work your way to harder problems.

The Biggest Time Trap When Preparing for USACO

The final component to an effective practice strategy is to make sure that you’re actually spending your time practicing – and not procrastinating. I’ve also filmed a video about this with Yibo: The Biggest Time Trap When Preparing for USACO. 

What Does Procrastinating in USACO Look Like?

Certainly, the conventional methods of delaying tasks can still be observed in the context of USACO, such as watching television, taking a nap, and engaging in various activities instead of practicing as intended. However, a distinct form of procrastination is also widespread among many participants, where even though you may think you are being productive, you’re really just procrastinating. 

One example of this type of USACO procrastination is spending your time “becoming a Codeforces rating or USACO historian.” Essentially, rather than practicing problems, you’re spending your time looking at past contests and seeing who did really well, looking at who the past finalists were, or even perusing IOI results to find the best competitors. All this information is interesting for sure, but at the end of the day not useful at all for actually advancing in USACO. This isn’t to say that you shouldn’t do any of this, but make sure that you’re counting it as “fun” time rather than time actually spent practicing.

Another common form of USACO procrastination is spending your time reading a bunch of Codeforces blogs. Some blogs can definitely be useful, however many others are often about niche topics that will almost certainly never appear in a USACO contest. Even if your goal is to learn a concept relevant to your division, it is generally a better idea to get started by watching a Youtube video where they provide visual illustrations and examples rather than reading a fully textual blog.

Causes of Procrastination

Often, competitors feel inclined to procrastinate because they don’t really know how to study for USACO. They try a preparation strategy but don’t see results, so they’re not sure what to do next and end up procrastinating.

If you’re ever not sure what to do next, and find yourself searching on Quora, Discord, Coderoces, etc. to look for an “optimal” preparation strategy, this still falls in the category of procrastinating. You’re never going to find an “optimal” strategy – the best thing you can do in your position is to come up with any routine and run with it. If you notice any issues with the routine down the line, you can always iterate on your routine until you find something that works for you. The important thing here is that you need to start by doing something, which does not include googling.

Why You’re Not Seeing Results

Before you start evaluating whether your prep strategy is working, make sure you’ve stuck with it long enough (a good guideline is having solved 20+ problems). 

If you still don’t think you’re making progress, consider how you’re evaluating progress in the first place. For example, if your metric is whether your contest results are improving, it won’t be accurate because contests are getting harder every year, or maybe you just weren’t as good at the problem that came up. Further, it’s possible that you have been making progress, but haven’t yet reached the threshold where you’re able to solve problems of a certain difficulty.

One way of evaluating progress is to look at the difficulty of the problems you’re able to solve. To determine how easy/hard a problem is, look at the promotion details in the corresponding contest to see how many people solved each problem (this no longer works for newer bronze/silver problems, but still works for all the older ones). Easy problems will typically have been solved by everyone, whereas harder problems will have a lot less solves. If you previously could generally only solve the easy problems, but noticed that you’re now able to get some of the medium level problems, that’s a clear indication of your improvement!

If, after changing how you evaluate your progress, you still feel like you’re not improving, it’s time to rethink how you’re practicing. One cause of little to no improvement is that you’re not solving problems at your level. For example, if you’re randomly picking problems to solve, they can often be too hard or too easy, which is not optimal because you won’t learn from them. Instead, make sure you’re finding problems in the sweet spot – one’s that aren’t too easy or too hard.

Sample Preparation Strategies

One method of preparing is to use Codeforces. Start at a rating where you’re only able to solve 25% of the problems and practice them until you’re able to get 75% of them. Then, increase the rating by 100-200 points and repeat the process.

Replicating this method is slightly harder for USACO because there isn’t a numerical rating assigned to each problem. However, you can still follow a similar process by solving the easiest problem of each contest, then moving on to the medium level problem in each contest once you’re comfortable, and finally solving the hardest problems.

Conclusion

In conclusion, effectively preparing for USACO amidst a bustling high school schedule is a multifaceted endeavor that hinges on strategic time management and focused practice. Riya's journey to USACO camp and MIT underscores the importance of prioritizing quality over quantity in practice sessions. By identifying periods of high mental acuity, such as weekend mornings or post-nap afternoons, students can maximize their practice efficiency. Moreover, it's crucial to balance the pursuit of quality with a sufficient quantity of practice, which may involve making tough decisions about extracurricular commitments.

Misconceptions about needing to be in perfect mental condition to practice should be dispelled; consistency remains key, even on off days. As for the content of practice, honing in on relevant topics and applying them through active problem-solving is more beneficial than passively absorbing information. For those in the Platinum division, focusing on common topics yields better returns than spreading oneself too thin across numerous niche areas.

Finally, avoiding the pitfalls of procrastination by engaging in meaningful practice and not getting sidetracked by less productive activities is essential. Progress should be measured not just by contest results but by the increasing difficulty of problems one can tackle. If progress stalls, reassessing one's approach to practice is necessary, ensuring that the problems worked on are neither too easy nor too hard. By following these strategies, students can create a tailored preparation routine that evolves with their needs, leading to continuous improvement and success in USACO competitions.

Mastering USACO Silver: An In-Depth Guide to Advancing in Competitive Programming

Introduction

The USA Computing Olympiad (USACO) is a prestigious programming competition divided into four divisions: Bronze, Silver, Gold, and Platinum. Among these divisions, passing USACO Silver stands out as one of the most challenging tasks, arguably second only to qualifying for the USACO Camp. This is because the gap in terms of difficulty and algorithmic maturity between Bronze and Silver is very steep compared to other divisions. While past coding or math competition experience might suffice for advancing from Bronze to Silver, Silver demands a significantly more extensive approach. Not only does it require learning a handful of new algorithmic concepts and data structures, but it also requires competitors to have a thorough understanding of exactly when and how to apply each one.

Especially with the increasing difficulty of contests, which particularly impacts the Silver division, participants must dedicate a substantial amount of time to learn new algorithms and hone their problem-solving skills. In this comprehensive blog post, we aim to provide an in-depth understanding of the USACO Silver division, covering everything necessary to advance to USACO Gold in your next competition! 

Note that the rest of the blog assumes that you have already passed Bronze (or are already very familiar with the division), and thus will not cover prerequisite information from Bronze.

Concepts You Need to Learn For USACO Silver

To begin preparing for Silver, we recommend starting by learning each concept individually before practicing on past contest problems. Jumping straight into practicing on past problems before learning the concepts can often be counter productive, because it’s very difficult to figure out these concepts on your own (especially while trying to solve a problem) and will spoil the problem for future practice. Instead, the recommended approach is to learn each topic individually, followed by practicing with a curated list of problems (e.g., the USACO Guide or Codeforces) that require that concept. 

Beyond the topics covered in USACO Bronze (programming fundamentals, recursion, basic data structures, and sorting), USACO Silver introduces a wide variety of new concepts. 

Prefix Sums

Prefix sums have a wide range of applications: most notably, they enable computing range sums over arrays in constant time. Generally, you should think about prefix sums whenever you want to optimize some sort of operation or query over a range. In addition to prefix sums, it’s important to learn the difference array technique and computing 2D prefix sums. In modern USACO Silver problems, prefix sums are generally not the crux of the problem solution (i.e. the question will never just be to compute a certain operation over a range). However, they still serve as an important component in optimizing efficiency in a more complex solution.

Binary Search

Binary search is an efficient algorithm to search for values over a sorted array, reducing time complexity from O(N) with linear search down to O(log N). Lower and upper bound binary search are variations of the binary search algorithm, which can efficiently find the first and last occurrence of an element in a sorted array respectively.

It’s also important to learn the technique of “binary searching for the answer,” which can typically be used when the problem asks you to find the maximum or minimum value of some variable that satisfies a certain condition. Many of the past and recent USACO Silver problems utilize this technique.

Data Structures

In addition to a solid grasp of foundational data structures such as static and dynamic arrays, unordered sets, and maps, Silver level proficiency necessitates a thorough command of several additional data structures. These include stacks, queues, priority queues, ordered sets, ordered maps, and linked lists. While these data structures are crucial tools for optimizing the time complexity of solutions, they are not intended to be the sole focus of problem-solving. Problems at this level in USACO will demand the adept integration of these structures within more complex solutions, highlighting their supportive role rather than being the sole solution component. As such, simply knowing how each data structure works is not at all enough to master this general concept, instead competitors need to know the ins and outs of the tradeoffs between each data structure and how to apply each one effectively.

Graphs, Trees, and Traversals

Graphs is by far the most important topic in USACO Silver. The concept is simple: representing a network of relationships via a collection of “nodes” connected by “edges.” Every Silver contest will have at least one graph problem. Graphs also happen to be one of the most diverse types of problems. Some important concepts within graph theory are as follows:

• General terminology (nodes, edges, directed edges, connected components, cycles, etc.)

• Representing graphs with adjacency list vs. matrix

• Depth-first and breadth-first traversal

• Applying graph traversals to the flood fill algorithm on grids

• Special types of graphs, most notably trees (connected acyclic graphs) and functional graphs (directed graphs in which all vertices have an outdegree of 1)

Typically, whenever a problem mentions a network of objects that are connected in some way, it’s a clear indication that the solution involves graphs (i.e. barns connected by paths, friendships between cows, etc.). 

Generally, all silver graph problems will require you to perform some sort of graph traversal, which typically boils down to using depth-first search. Many silver problems in USACO will also contain special types of graphs, which as mentioned earlier include trees and functional graphs. You’ll know you’re facing a tree problem whenever the problem statement mentions a connected graph with N vertices and N - 1 edges, a graph where every pair of nodes are connected by a unique path, and/or a connected graph that does not contain any cycles. Functional graph problems are generally not as obvious (it may not even be obvious that it’s a graph problem in the first place), however will generally boil down to exploiting cycles within a directed graph. 

Two Pointers and Sliding Window

The two pointers technique involves moving two “pointers” rightwards across an array, typically to search for a pair of indices that satisfy some condition. Since each pointer only passes through the array once, this technique is used to optimize a solution that brute forces over all pairs of indices in an array, which would take quadratic time, down to an approach that only takes linear time. 

The sliding window technique is a special case of the two pointers technique, where a fixed distance is maintained between the two pointers. This approach considers all constant size subarrays of an array, maintaining and updating data between each subarray. 

It will almost never be obvious when either of these techniques should be applied, as problems generally become much simpler once you know that one of the two techniques can solve the problem. As such, you should always have these floating around in the back of your mind whenever you’re solving a USACO Silver problem.

Greedy Algorithms

The Greedy approach is an algorithmic strategy that constructs a solution incrementally, selecting each subsequent piece based on the most apparent and immediate advantage. In other words, it finds the globally optimal solution by taking locally optimal choices at each step. Greedy algorithms are different from all the other concepts listed in the sense that they can vary a lot from case to case, and are solely defined based on the principle of choosing the local optimum.

It’s important to note that a greedy approach will not always work, as there are many instances where locally optimal steps do not lead to a globally optimal solution. However, greedy solutions are generally simple to implement, so if you are ever unsure of whether a problem can be solved using greedy, just implement it and see if it passes (this may not be a good idea for more complex problems). If it does, great – you’re done, and you didn’t even have to waste time proving to yourself that your solution works! Otherwise, back to the drawing board!

Coordinate Compression

Within USACO Silver, coordinate compression is a rare, but nonetheless important, technique in which you compress values from a large range into a smaller range. The process involves assigning each value within a list to its corresponding index if the list were sorted.

This technique is useful whenever you do not care about absolute values, but rather the relative ordering of the values. Note that you will not always need to use coordinate compression – only use it when you need the relative values to be small for whatever reason (i.e. you want to use the values as array indices, which would require compressing the values down to a smaller range). Coordinate compression can also be applied to the 2-dimensional case, and can often be paired with 2D prefix sums.

Ad Hoc

Ad hoc is the only concept that you do not have to learn – because it isn’t a concept! Ad hoc problems are those that do not fall in a well-defined category (i.e. the main solution does not involve any of the specified concepts in Bronze or Silver). Instead, they involve some clever insight or observation about the problem itself. As a result, these types of problems require very strong problem solving skills. 

The only way to really prepare for ad hoc problems is to practice a bunch of them! Ad hoc problems can only really be solved by having strong problem solving, and the only way to get better at problem solving is to practice. 

Resources and How to Prepare For USACO Silver

A comprehensive list of resources available can be found on the USACO Resources Page. Below, we’ve listed resources that competitors have historically found to be most useful for each stage in preparing for silver: learning each concept, practicing each concept, and preparing for contests.

Learning USACO Silver Concepts

There are a ton of free resources available online to learn and master each concept required in USACO Silver. In particular, the USACO Guide does a great job at providing links to videos, articles, and textbooks that explain each concept in detail. 

If you want to follow a textbook specifically geared for competitive programming, some great resources include the Competitive Programmer’s Handbook by Antti Laaksonen (note: many of the topics listed are Gold and Platinum topics, out of the scope of Silver) and An Introduction to the USA Computing Olympiad by Darren Yao.

Another way to learn Silver concepts is to take an online algorithms course provided by a college. Coursera hosts many good courses, most notably Algorithms Specialization by Stanford University and Algorithms Part I and II by Princeton University. While they cost money, Coursera allows you to audit them for free, or to apply for a fee waiver (it’s fairly easy to get approved as a high school student). In addition to covering relevant topics for USACO, they provide interesting projects and exercises to apply what you’ve learned, which can help place these concepts in a broader context and give you a taste for what college-level computer science classes are like. If your only goal is to prepare for USACO, however, these courses won’t be as efficient of a way to learn the concepts you need.

If you prefer learning in a more structured manner, or don’t learn on your own effectively, you may want to consider signing up for a USACO class. Classes follow a set curriculum and pace, and provide more personalized help through teachers. However, classes do cost money, and quality may vary between different organizations – do your research before signing up for one!

Practicing USACO Silver Concepts

After learning each concept and how to implement them, the next step is to practice using that concept in past problems. Often, it’s wise to organize your practice by topic – for example focusing on practicing DFS one week and then practicing two pointers another week.

The USACO Guide, once again, is an amazing resource to practice concepts once you’ve learned them. It provides a curated list of problems for each concept, enabling targeted practice once you have learned each one. 

Another useful resource for targeted practice is Codeforces, which is the biggest online site that hosts competitive programming contests. It’s also a great resource if you want to practice, but want to save past USACO Silver problems for when you feel more comfortable. To organize your practice by concept, navigate to the problem set tab and filter the problems by a specific tag (i.e. the concept you want to practice) and difficulty range (1200 - 1900 is generally a good range for Silver). For a comprehensive guide on how to utilize Codeforces, check out our blog here.

How to Prepare For USACO Silver

Once you feel comfortable with all the concepts tested in USACO’s Silver division, as well as how to implement them in past problems, it’s time to prepare for upcoming contests. Do not continue practicing with concept lists! While they are great for learning concepts initially, relying on topic lists to prepare for contests can be counterproductive, as it’s much easier to solve a problem if you already know what algorithm/data structure you are supposed to use beforehand. 

The best way to prepare for upcoming contests is simply to practice on past problems! A great way to do this is to go through problems in the past contests page on USACO, starting from the 2016-2017 contest season and working your way through to the more recent contests. Newer contests are typically harder than older ones, so by practicing in chronological order, you’ll gradually face harder problems as you improve through more practice. 

If you have run out of USACO Silver problems to practice, or want to save the remaining ones for later, Codeforces is a great resource to find a ton more problems and contests. 

What to Do if You’re Stuck In USACO Silver

Many competitors often run into some scenario where they do really well in Bronze and pass, but find themselves stuck in Silver for several contests—maybe even a year or two. If this is happening to you, it’s time to re-evaluate how “ready” you think you are for upcoming contests, and why your expectations of passing are not matching up with your past results. 

Maybe you’ve learned all the Silver concepts and have practiced them on a bunch of problems already, or you’ve been able to solve 50% of all past Silver problems already. In these cases, would it be reasonable to expect to be promoted in the next contest? In many cases (unless you’re naturally super talented), no! Our blog post about Closing the Gap Between Expectations and Reality goes into this topic in depth. Essentially, even if you’ve solved 50% of all past Silver problems already, the problems you’ve solved are likely to be roughly the easiest 50%. However, modern contest problems are all typically on the harder end of the difficulty spectrum, meaning even though you could solve half of the Silver problems, you won’t be able to solve any problems in a contest because the level of difficulty you can handle does not encompass the contest difficulty. 

If you truly want to anticipate success for an upcoming contest, you should reach a point where you can solve more than 90% of all USACO Silver problems. At this point, it is a lot more likely that all three contest problems will fall within the range of what you can handle — and thus you should expect success in these cases.

What if you’ve reached a point where you can solve all past Silver problems, but you still find yourself struggling in contests? This brings us to the next topic: contest strategy.

Silver Contest Strategy

Having a strong contest strategy can make or break your contest performance. In fact, during USACO camp each year, the coaches host a special lecture focused solely on developing a strong contest strategy. And every time, the campers see their scores shoot up after implementing the contest strategy.

So, what makes a good contest strategy? The key distinction between practicing on your own time and competing in contests is the time limit. While 4 or 5 hours may seem like a lot of time – it really isn’t. Thus, being able to allocate your time well is absolutely crucial for succeeding in contests. 

Riya filmed a great video detailing contest strategy in depth, and we also have a blog post regarding contest strategy. The key takeaway from the video is to take practice contests with the same time constraints as a real contest. During these contests (and actual contests too), keep a contest log where you note down what you are currently working on every 15 minutes. Maintaining this log can help you identify time leaks during contests: if you notice that you’ve been working on the same problem for one and a half hours without significant progress, you should choose to cut your losses and move on to a different problem, coming back to the current problem later. 

After the contest is over, analyze your performance. Did you allocate too much time on a single problem? Were you too caught up in debugging because you didn’t plan out implementation well enough? Could you have solved a problem with better time management? Asking questions like these can help you identify mistakes you’ve made and learn from them, making sure that you do not repeat these mistakes in the future.

How Much You Should Practice

A lot of competitors often ask the question, “how many hours a week should I put into USACO to pass X division in Y time?” The answer to this question is different for everyone. It could take some competitors 2 months to pass USACO Silver practicing 2 hours a week, and other competitors 10 months practicing 5 hours a week. 

Instead of comparing yourself to how much others practice, or frantically searching online to find a routine that worked for someone else, you need to figure out what works for you. To achieve this, create some goal in which you hope to promote by, and allocate time throughout your schedule so that you can consistently make progress every week. If you find that you’re not progressing as fast as you need to, either put more hours into practicing every week or reconsider if your goal is realistic. Another option is to find a USACO coach, which can often make your practice and improvement a lot faster, giving you time to focus on strengthening the rest of your college application.

At VPlanet, we have private coaching programs starting from USACO Bronze all the way up to USACO Platinum.

Coaching from VPlanet Coding

If you’re super busy, then you need our program, so that you can advance faster and spend your time more efficiently. If you can get half your time back, then all those remaining hours can be spent on something else to make your college apps that much more competitive.

Here are 5 key benefits that we provide over other alternatives:

Comprehensive curriculum for each division

VPlanet provides dozens of hours of video content with in-depth algorithms and problem walkthroughs, covering all the knowledge a student needs to know to become successful. Additionally, our curriculum teaches the essential problem-solving skills that are required beyond the knowledge of algorithms.

Carefully curated problems

Practicing on your own can be frustrating and inefficient. We know what it’s like to spend 2 hours thinking through a problem just to give up and read a solution you can barely understand. VPlanet has handpicked 100+ problems for each division, ensuring that the problems students work on are never too easy or too hard. We guarantee that each problem has just the right level of difficulty to optimize students’ improvement trajectory. 

Daily support from coaches

If students are ever stuck or confused, VPlanet provides daily support in the form of Facebook group discussions, Q&A, and one-on-one sessions with highly-experienced coaches. These sessions maintain a very small ratio between students and coaches to ensure that everyone receives as much personalized help as possible. 

In contrast, a typical USACO class can have as many as 30 students assigned to one teacher, with only 1-2 class sessions per week to ask for help. This class environment makes it difficult to ask for help and risks leaving many students behind.

Work at your own pace

An inevitable issue with USACO classes is that they fail to account for each student’s individual skill level. This issue guarantees that either a significant number of students are falling behind in class, or the class is too slow for many high-achieving students. VPlanet overcomes this issue, enabling students to go at the pace they want with regular support from coaches.

Advance faster

We find that VPlanet students tend to advance at a much faster pace than others. Our carefully crafted curriculum and sessions with coaches provides just the right amount of content and personalized support for students to improve as fast as possible. This leaves our students with more time to focus on other activities to strengthen their college applications.

Conclusion

Mastering the USACO Silver division requires a multifaceted approach, delving into an array of advanced concepts and problem-solving strategies. This comprehensive guide serves as a roadmap for aspiring participants, emphasizing the importance of deeply understanding concepts, targeted practice, and realistic expectations. Transitioning from theoretical comprehension to practical implementation is pivotal, coupled with an emphasis on effective contest strategies to manage time and learning from mistakes. By embracing these principles, individuals can navigate the challenges of Silver, enhancing their competitive programming skills and setting a solid foundation for future success in higher USACO divisions.

How USACO Camper, Grace Cai, went from USACO Bronze to USACO Camp to MIT

Here is the full Q&A, where I talk with Grace about her journey through competitive programming: How USACO Camper, Grace Cai, went from USACO Bronze to USACO Camp to MIT

Hello, everyone! I'm Riya, and today we have the pleasure of hosting a remarkable guest, Grace Cai. Grace, a former USACO camper, will be sharing her inspiring journey from USACO Bronze to USACO Camp to MIT. We'll delve into her experiences and strategies, and hopefully provide some invaluable insights for aspiring programmers.

Early Challenges and the Path to Silver: 

Grace's journey into the world of competitive programming began in ninth grade when she attended a STEM-focused high school, Montgomery Blair High School in Maryland. Introduced to USACO through her school's computer club, she was immediately intrigued by the world of algorithms and logical problem-solving.

In her initial encounters with USACO, Grace admits to facing challenges, particularly as she was coding in Python. Although she swiftly progressed from Bronze to Silver, the transition was not without its struggles. Concepts like BFS and DFS remained elusive, and she realized she needed a more structured approach.

Serious Learning and Algorithm Mastery: 

It was at the end of her ninth-grade year that Grace embarked on a serious journey into algorithms. She attended a specialized camp designed to prepare students for USACO, dedicating two weeks to intensive algorithmic coding. Here, she honed her skills in areas like shortest path algorithms and MST (Minimum Spanning Tree), laying the foundation for her future success.

As she delved deeper into algorithms, Grace began exploring USACO Platinum topics. Networking with her peers, who were already in the Platinum division, proved instrumental in her learning process. She also scoured the USACO website and utilized Codeforces, specifically the Division 2D and 2E problems in the problem set, to enhance her problem-solving abilities.

Furthermore, Grace highly recommends participating in Codeforces contests. The platform's categorization of problems by tags and its emphasis on logic and solid coding skills made it a valuable resource. Codeforces contests also provide the unique challenge of not displaying individual test cases, requiring participants to ensure the robustness of their solutions.

Problem-solving Approach: 

Grace's approach to competitive programming stands out for its meticulous and analytical strategy. Her methodical approach revolves around maintaining a problem log, where she records her solutions, improvements, and personal reflections for every problem she attempts. This practice has proven invaluable in her journey, offering several key advantages:

• Identifying Areas for Growth: By documenting her solutions and reflecting on her thought processes, Grace gains a deeper understanding of her strengths and weaknesses. She can pinpoint specific areas where improvement is needed, allowing her to tailor her practice to address these gaps effectively.

• Tracking Progress: The problem log serves as a progress tracker over time. Grace can revisit her previous attempts, comparing her past and current solutions to gauge her advancement. This historical perspective motivates her to strive for continuous improvement and provides a clear sense of accomplishment as she witnesses her growth.

• Effective Learning from Mistakes: Grace doesn't shy away from recording mistakes or suboptimal solutions in her log. Instead, she views them as valuable learning opportunities. Analyzing her errors and understanding what went wrong empowers her to avoid making similar mistakes in future challenges.

• Strategic Topic Selection: Grace's approach to problem selection is equally calculated. She concentrates on recent problems that align with the specific topics she aims to master. Rather than randomly picking problems, she strategically targets those that present new challenges or delve into unfamiliar concepts. This approach ensures her learning remains purposeful and relevant to her competitive programming goals.

In essence, Grace's structured and analytical approach is a blueprint for success in competitive programming, offering a clear path to improvement and excellence.

Optimizing Study Hours: 

Grace's study hours during her intense summer learning varied between 8 to 14 hours per day. She dedicated herself to putting in the long hours every day, as solving more problems and getting in more repetitions can drastically improve problem solving skills.

However, in her tenth-grade year, Grace realized that quality work mattered more than quantity. She emphasized the importance of analyzing her solutions, learning from her mistakes, and pushing herself to tackle difficult problems. This shift in focus significantly contributed to her rapid improvement.

Hard Work Paying off

Grace's determination and meticulous preparation paid off during the December contest of her tenth-grade year. Not only did she manage to get a perfect score on silver, but she also achieved a high score on the Gold division, allowing her to advance directly to Platinum in one contest! This remarkable achievement demonstrated the results of her dedication and analytical approach.

However, her hard work extended past just the confines of Gold. Within her first contest in Platinum, Grace was able to score a 556 after solving one full problem, and achieving partial credit on the others. This was a big achievement for her, as she was already reaching camp level scores despite only being in silver just one year prior. However, this was just the beginning, as she would go on to increase her scores dramatically over the next few contests. 

Practicing for Platinum

Between her first and second contest in Platinum, Grace’s score increased almost 200, which is half of a problem! Between these contests, Grace practiced largely the same kind of problems as before - division 2 Codeforces and Platinum problems- but with one big change: topic lists. 

Grace met many fellow competitors who were also studying for USACO, and received many resources from them, the most effective being a list of topics, along with different problems that one could use to reference and practice those topics. The problems came from various sources, including Codeforces, Peking University Online Judge, ACM, spoj, and of course, USACO. She was able to utilize this resource to learn many new algorithms that she had never heard of before and get lots of practice with the algorithms she was already knowledgeable in. Plus, she made many new friends!

However, Platinum’s curriculum was simply too large to cover; topics that had never shown up before could come up in the next contest. Thus, despite coming across unfamiliar topics in contests, Grace decided to not get hung up on them, and instead prioritize topics that are most likely to show up, and become an expert in those areas. This maximizes the value of her practice, as a topic that may show up once every 3 years is never worth practicing as much as Dynamic Programming. Luckily, the topic lists that Grace received had a priority within them, and Grace was able to focus on more important topics within her practice. 

Qualifying for Camp

Throughout the year of 2017, Grace went on to set more and more impressive scores. In January, Grace achieved a 556, and in the February contest, Grace scored a 744, which was two full problem solves along with partial credit on the last problem. These scores were more than sufficient for camp, and in 2017, Grace was selected as a USACO finalist. 

Motivation

Sitting down and coding for 8-14 hours in one day is understandably a chore to many, and people often get burnt out when practicing this much every day. For Grace however, doing competitive programming is more of a hobby, and she always found her practice sessions exciting and peaceful, as it allowed her to express logic in a nice way. In fact, Grace emphasizes that having a natural interest in programming is incredibly important. Often, people do USACO purely for the sake of college applications, and while this is a valid motivation, if you don’t have the natural interest in it, you won’t be able to put in the long hours when you need to. 

Of course, even with a passion for problem solving, thinking about hard concepts for hours on end is incredibly tiring. Thus, when faced with fatigue, Grace would take a five minute break, and then force herself to come back to it to avoid procrastination and distraction. 

Another technique Grace used to gain motivation was to get herself into a routine. Every day after school, Grace would immediately open up a problem and start thinking about it. Then only at night would Grace do her homework. This made it so that it was as natural as brushing her teeth for Grace to practice every day. In fact, competitive programming worked as more of a de-stressing activity for Grace from things like school and homework. Even if the problem was hard, focusing on one thing without a care for anything else at the moment was really relaxing.  

Debugging

Like many, Grace initially had lots of trouble with debugging. When she was competing in the Facebook Hacker Cup in 9th grade, she started using C++ for the first time, and began learning the standard library. As she was learning how to use C++’s map for the first time, Grace ran into a bug that took her around eight hours to fix! In the end, the reality with programming in general is that you will run into really simple bugs that can take many hours to find, however, there are many ways you can improve at debugging and avoiding bugs in the first place. 

As Grace improved and rose in the divisions, she was able to greatly improve her debugging skills. The first skill Grace emphasizes is knowing where to find the bugs. For example, you are very unlikely to have bugs when reading in input, so you can mostly skip past that when debugging. In general, identifying places where bugs are most likely to reside can drastically decrease your debugging time.  

Another thing Grace emphasizes is readability. Oftentimes, less experienced programmers introduce lots of redundancy and unnecessary complexity into their code, such as unnecessary break statements, or implementations that technically work but are very unconventional. Having a clean implementation that is nicely structured can greatly speed up the debugging process, and also helps avoid bugs. To help improve code cleanliness, Grace suggests thinking about the problem more clearly and planning out implementation before jumping right into the code.  

Many programmers, especially those using C++, will also have a long template, including a list of “#define”s. While these are not inherently bad and can definitely speed up implementation if one is really familiar with them, they can clutter your code up, and make it harder to understand the code when reviewing it during debugging. Grace initially had a long list of macros, but eventually got rid of all of them except for a few that were most commonly used, such as “f0r” to represent a for loop starting at 0. However, macros that are useful for debugging are those that can help with printing. For example, a macro that can print out everything in a list in one statement can speed up debugging, as you are able to print your data and reevaluate more quickly.  

Grace’s Advice and Journey’s end

Grace emphasizes the importance of enjoying yourself when doing USACO. If you don’t enjoy problem solving, then the long journey to achieving milestones in USACO will be painful, especially the grind to Camp. Furthermore, high school is the best time to do competitive programming, since it builds a strong problem-solving and programming foundation, and when you’re in college, there are many other opportunities within computer science to explore. 

After becoming a finalist in 10th grade, Grace went on to do a lot of impressive computer science research so that she could explore other areas in computer science. However, she still really enjoyed competitive programming and looks back fondly upon it as an exciting experience.

Q&A

If I’m a junior, and I’m shooting for USACO camp, what strategy should I use in Platinum Contests?

In the recent contests, USACO added a concrete list of subtasks for each problem, making contest strategy more important than ever. 

For a contest strategy, Grace recommends identifying and solving the easiest problem first, getting full credit if possible. This is because having a problem solved can greatly boost your confidence in solving the other two problems, which is essential for the mental game in contests. However, at first, it can be difficult to even identify which problem is the easiest and which ones are the harder problems, so how do you do it? Grace emphasizes the importance of thoroughly reading ALL of the problems and subtasks as soon as you begin, as it can give you great insights into the difficulties and potential solutions for all the problems. 

Furthermore, Grace suggests dedicating the first hour of the contest to reading the problems and then brainstorming solutions without actually coding anything up. This approach ensures that contestants don’t waste time on coding up easy subtasks, and instead spend the time trying to figure out the whole problem, which can save implementation time. However, it is also important to acknowledge the power of subtasks; if you are unable to find the full solution for a problem in a fixed time period, you should pivot to subtasks instead, as getting 40% on a problem and 60% on another puts you in the same spot as one full solve. In the end, finding a good balance between subtasks and the full solution is crucial. 

How do I continuously make progress on a problem in a contest even after I’m stuck?

Oftentimes, the situation arises that a contestant gets a lot of ideas about a problem in the first ten minutes thinking about it, and afterwards, makes little to no progress. For this common issue, Grace suggests two solutions. 

First, if you have been stuck on a problem for a good amount of time, switch problems. Thinking about another problem and then coming back can generate a lot of subconscious thoughts about the problem. Furthermore, your mind is more refreshed on the problem after switching and coming back, so you can potentially see perspectives that you hadn’t seen before, and solve the problem using these new insights.  

Second, think about different ideas and ways to approach the problem. It’s really easy for a competitor to get stuck in a loop where they keep trying to solve the problem using the idea they came up with first, thinking that the idea has led to part of a solution and that it must lead to the full solution as well. However, this is not optimal, as ideas that work for part of a problem can be a dead end for the rest. Thus, rethinking the problem and trying out different approaches can really help with getting unstuck. For generating different ideas for a problem, Grace recommends drawing out small test cases and breaking the problem down into subtasks, and exploring all the possible ways to solve them. 

Lastly, Grace emphasizes the importance of persistence. Even if you’re stuck for thirty minutes or an hour, with enough thinking, the right idea can always pop into your head. 

What are the best (free) resources for studying for USACO?

The best resources, and the ones that Grace used, are online problem libraries, in websites such as Codeforces, spoj, poj, etc. Furthermore, make sure to use these resources effectively by reading the solutions thoroughly and understanding why the solution works for problems that you were unable to solve. 

If you are worse at math, is it better to focus on math problems?  

Grace thinks that while math skills can be beneficial, they are not as critical as problem-solving abilities for USACO success. Many aspects of USACO require a distinct skill set, and a strong focus on problem-solving is paramount.

What is more effective, doing blind practice, or topic-based practice? 

Grace considers topic-based practice valuable for mastering specific problem-solving strategies. However, she also emphasized the importance of attempting random problems to assess adaptability and versatility in applying problem-solving skills. Thus, Grace recommends starting with topic-based practice to gain valuable algorithmic skills, and then transitioning to random practice to develop problem-solving skills. 

Conclusion

In conclusion, Grace Cai's insights and experiences provide invaluable guidance for USACO participants at all levels of proficiency. Her journey from the bronze division to platinum underscores the significance of dedication and continuous learning in the realm of competitive programming. Additionally, Grace invites those interested in art to visit her art Instagram account under the username "introoging", where she showcases her creative works. In parting, she encouraged all aspiring USACO students not to be discouraged by divisions or competition levels, emphasizing that hard work and perseverance can lead to rapid progress in competitive programming.

How to Gain and Maintain Motivation When Practicing for USACO

Oftentimes, the hardest part about getting better at USACO and competitive programming in general is motivation. Today, I will discuss ways to be more motivated when practicing. 

The importance of motivation

Motivation, despite being intangible, is the most important force in competitive programming, or anything in life for that matter. In fact, it is the main barrier that separates the better coders from the worse. While algorithmic knowledge is very important, the main distinguishing factor between being able to solve a problem and being stuck is problem-solving skills, and problem-solving skills can only be developed through repeated practice.

However, it is much easier said than done. Burnout is very real, and can hit you at any moment. Even if you have become disciplined enough to practice for 10 hours every day for a whole year, the very next day you could want to quit. Thus, being motivated, and maintaining motivation is the most important thing to being successful as a competitive programmer. 

Competitive Programming Sites Outside of USACO

The first way to improve your overall motivation is to compete on competitive programming websites aside from USACO. As you already know, there is a long gap between March and December, where there are zero USACO contests. This dry spell during the summer and the first semester of your school year can kill your motivation, as it will feel like you are practicing for nothing, with no tangible results to measure your progress or to show for. 

The way you can remedy this is by competing on other competitive programming sites, such as Codeforces, LeetCode, CodeChef, AtCoder, etc. Within these four sites, there are almost 4 contests a week that you can work with. Furthermore, each one has its own rating system that can assist you in measuring your progress. If you compete on these sites regularly, you can not only measure your progress, but you can also experience the excitement of seeing yourself grow; seeing your rating graph steadily increase gives me a sense of accomplishment like nothing else. 

Contests are also much more interesting than normal practice. When doing a contest, time will fly by, and two hours will feel like nothing. Also, if you are competing under time pressure, you’ll tend to automatically work harder towards solving a problem. It still counts as practice as well, since you are doing problems and coding them up to completion. 

Perhaps the greatest benefit of contests is developing your contest skills and speed. All programming sites outside of USACO tend to emphasize speed, as they must cater to programmers of all levels, so the problems can greatly vary. Thus, solving the easier problems faster becomes more and more important. As you practice solving easier problems faster, you’ll be able to translate those skills into solving harder and harder problems faster as well. Furthermore, you’ll be able to simulate the pressure that you face in a USACO contest, and become more comfortable and confident when faced with that pressure when the season rolls around. 

Virtual contests

Taking the fact that contests are more interesting to the extreme, you can do virtual contests. Under the right conditions, taking a virtual contest can put the same time pressure on you as actual contests, pushing you to practice harder and solve more problems. By doing virtual contests, you can grind through 5 problems without even knowing it, passively increasing both your problem-solving and contest skills even more than before.

The site that I would recommend most to do virtual contests in is Codeforces. It has an incredible built-in virtual contest feature, and there have been so many contests on Codeforces that you’ll never run out of contests to do a virtual one on. Furthermore, they have contests for all divisions; if you are bronze, I’d recommend doing division 3 contests. For those in silver and gold, I’d recommend doing division 2 contests, and for those in platinum, I’d recommend doing division 1. 

To participate in a virtual contest on Codeforces, click on the “Virtual Participation”, choose a time, and get started!

What about if you are unable to take virtual contests seriously, knowing in the back of your mind that they will never matter as much as a normal contest? I cannot deny that virtual contests will never have the feel of a real contest, but there are many ways you can simulate the real thing. First, try doing virtual contests with friends, and competing against them. This can motivate all of you to improve. Furthermore, there is a Discord bot that allows you to do “rated” virtual contests. The bot is called the TLE bot, which you can read about here. You can either set this bot up on your own server, or you can join the AC server to use it (the invite link is in the same link). With this bot, you have a virtual rating that changes every time you do a virtual contest, and you can use that as motivation to grind out virtual contests. 

An example of how to use the TLE bot’s virtual rating system.

The best part about virtual contests is that you can do them on your own time, and whenever you want! Codeforces contests or contests from the other sites can be at awkward times sometimes, so it is understandable if you can’t make it to all of them. As such, virtual contests are perhaps the best replacement. 

Think of virtual contests and normal contests as stepping stones for USACO. Use virtual contests to constantly improve problem-solving and contest skills between the live Codeforces contests, and use the live Codeforces contests to improve between the USACO seasons.

To start, I’d recommend doing virtual contests of the Codeforces Educational contests. They provide the most learning value, and are very fun and concise!  

Doing harder problems

As you may have heard many times, the sweet spot for the difficulty of problems you should practice is just above your skill level. You should be doing problems that you are unable to solve 50% of the time, and when you do solve them, it should have taken more than an hour. When you finish such a problem after a long, hard battle, the sense of accomplishment it brings is unlike anything else. For starters, after you finish a live contest or virtual contest, always try to upsolve (solving the contest problems after the contest) the problem right after the last one that you were able to solve. 

On the right side of Codeforces’ Problemset tab, you can filter problems for difficulty. A common strategy is to find a difficulty that is just above your skill level, and once you master it, move up in difficulty.

However, if you choose problems that you can solve 50% of the time, the half of the time when you can’t solve it, it will kill your motivation a bit. To remedy this, utilize editorials/solutions. If you find yourself losing motivation fast after not being able to solve a problem, simply go to the editorial. Make sure you take note of why you weren’t able to make the correct observation to solve the problem, so that doing problems where you need to look at the solution isn’t a waste of time. Even after you look at the solution, try to code it up yourself. If you find yourself having to look at the solution too often, simply move down in difficulty for problems you are practicing. 

Skip Tedious Tasks if you Must

Imagine this: you’ve been looking at a Codeforces problem for two hours, and after a long fight, you finally give up and look at the editorial. You realize that you missed one simple observation that would’ve pushed the solution you had in mind to completion. Now, as me and many others have advised, you should implement this anyway. However, for this particular problem, you know the implementation is incredibly long and unnecessarily tedious, and you can’t think of any reasons implementing this would help you in any way. 

Skip it! Even though it will never not be helpful to implement a solution that you’ve looked at, skip it if the implementation is too tedious. As long as you realize and take note of why you were unable to think of the observation or solution yourself, there is no need to spend an excessive amount of time on implementing the solution. It is better that you lose out on a bit of learning but still have the motivation to practice than procrastinate practicing simply because the next step in your practice is really tedious. 

It doesn’t have to be after you’ve looked at a solution. Even if you are able to think of the right solution to a problem, and have confirmed that the solution is right, you can rarely skip the implementation phase if you know it is long and will demotivate you greatly. 

Of course, skip implementations in moderation. These tedious problems WILL come up in a USACO contest, and you cannot skip them then. Thus, practice these implementations most of the time, but if you are feeling particularly demotivated by the dread of having to implement a really annoying solution, you can skip it once in a while. 

Friendly Competition

Friendly competition with peers can be one of the biggest motivators. I’ll share with you a story about none other than Riya, and her journey through the ranks of the USACO. This story underscores the pivotal role that friendly competition plays in not only enhancing one's coding skills but also in staying motivated. In her transformation from a Bronze-level coder to reaching the prestigious Platinum tier, Riya harnessed the spirit of a fierce rivalry to fuel her ambition and resilience. Let's explore how adopting a similar mindset could be beneficial for anyone in the competitive programming landscape. To watch the full video about her story, check out the video here.

Embracing Friendly Rivalry

Riya's initial encounter with friendly competition came when she observed a peer—whom we'll call Jane—progressing to the Silver division of USACO. Despite Riya's initial placement in Bronze, she recognized that she had just as much potential as Jane. This realization ignited Riya's competitive spirit. Jane's achievement wasn't a source of envy but a beacon of possibility for Riya. She intensified her study regimen and soon matched Jane's accomplishment by ascending to Silver.

The Impact of Belief

The story took a twist when, at one point, Riya found herself complacent, resulting in her stalling in the Silver division while Jane advanced to Gold. Seeing Jane conquer challenges encouraged Riya to revisit problems she had previously deemed too daunting. It wasn't about a placebo effect; it was a shift in mindset. The act of believing one can solve a problem often makes the crucial difference between giving up and persisting through difficulties.

From Gold to Platinum

Motivated by this newfound perspective, Riya not only progressed to Gold but continued her upward trajectory to Platinum. Her journey exemplified that a year of consistent effort and learning from silent, friendly competition can yield remarkable results. It was not only the adoption of better study techniques but also the motivational push provided by Jane's successes that spurred Riya on.

Broadening the Competitive Network

Upon reaching Platinum, Riya began to cultivate a wider circle of competitors. She engaged with fellow USACO participants, particularly her classmates, and used their progress as her own benchmarks. This friendly rivalry encouraged everyone involved to strive for greater heights, illustrating that collective success often stems from individual contributions.

Lessons from Teaching

Riya's experiences at the USACO camp, where she mentored students, further validated the value of friendly competition. She observed her students using each other's achievements as motivation, thus confirming that such competition is instrumental in overcoming more challenging problems.

Harnessing the Competitive Edge: Strategies for Success

The Power of Positivity

It is essential to keep the 'friendly' aspect in competition. The goal is not to outshine others but to use their progress as constructive motivation for self-improvement.

Expanding the Circle

Relying on a single person for motivation can be limiting. Riya advocates for having a network of competitors to ensure consistent inspiration and drive.

Community Engagement

Finding a supportive community can be invaluable. Platforms like the USACO forums or competitive programming Discords can connect you with motivated individuals.

Observing and Emulating

Monitoring and emulating the practice routines of active problem solvers on platforms like Codeforces can provide insight into effective study habits.

Collaborative Growth

Riya recommends finding a coding buddy, as mutual assistance in problem-solving can accelerate learning and progress.

Structured Learning Environments

Joining a class or group specific to your USACO division can provide a structured and competitive learning environment.

Takeaway

Friendly competition has the potential to make the solitary journey of programming feel like a shared adventure, full of camaraderie and mutual achievement. Riya's story is a testament to the fact that seeing others excel should inspire, not intimidate. This approach to competition not only spurs personal growth but also contributes to a healthier, more collaborative coding culture.

As Riya's experiences illustrate, leveraging friendly competition is a strategy that extends beyond mere rivalry. It's about embracing a mindset where others' successes catalyze our own efforts to excel. For those inspired by Riya's journey, remember that the essence of competition lies not in surpassing others but in continuously surpassing our own past performances.

Take Breaks

As with any activity, to avoid burnout, take breaks! Breaks can mean multiple things. After you’ve done a virtual contest, take a break! After you’ve practiced hard from Monday to Saturday, take Sunday off! After you have advanced a division as a result of hard work from the past few months, take a week off! These breaks can serve as a great reset for your mental state, and can bring you back better than ever. 

However, the most important aspect of a break is what comes after it. It’s easy to take a 1-hour break that becomes taking the day off, which then becomes taking the week off, and soon, you realize that you’re not even doing USACO anymore. Take breaks in moderation, and learn the discipline of coming back after your break. It’s perfectly fine to take a break after hard work, but it is not fine to completely stop after an accomplishment. 

Conclusion

In conclusion, sustaining motivation for competitive programming and USACO hinges on a blend of deliberate practice and strategic pacing. Participating in live contests on platforms like Codeforces hones your real-time problem-solving skills, while virtual contests solidify your abilities in a controlled setting. Pushing through tougher problems expands your expertise and resilience, essential for USACO’s challenging environment.

Friendly competition acts as a motivator, turning peer achievements into personal milestones to strive for. Yet, it's equally important to intersperse these efforts with breaks, allowing for mental rejuvenation and a fresh perspective on complex challenges.

By integrating these practices—targeted contests, skill-appropriate challenges, the encouragement of peers, and necessary downtime—you craft a balanced approach to competitive programming. This balance not only keeps your passion for coding alight but also ensures that the journey is as rewarding as the achievements it leads to. Whether you are a beginner or an experienced coder, remember that true motivation thrives in recognizing both the journey itself and the incremental progress made along the way.

"I could have gotten that if I just had more time", How to get those points!

Here’s the video where I discuss the same content: "I could have gotten that if I just had more time", How to get those points!

With the USACO December contest on the horizon, it's crucial to delve deeper into a crucial aspect of competitive programming: content strategy. Often overshadowed by the focus on algorithms and data structures, content strategy and implementation skills play an indispensable role in achieving high scores. In this comprehensive guide, we'll explore the intricacies of content strategy, its impact on your performance, and actionable tips to help you excel in implementing and debugging. Let's dive into the world of content strategy, demystify its components, and unlock its potential for success.

The Significance of Contest Strategy

To underscore the importance of content strategy, it's worth noting that in USACO camp, there is a dedicated lecture to it. This commitment to content strategy underlines its important role in competitive programming. As a coach, I firmly believe in its significance, having witnessed countless instances where content strategy transformed a participant's performance; I’ve even seen situations where a participant took their score from a 233 to a whopping 833 after mastering an effective contest strategy, securing them a spot in Gold!

Understanding the Contest Log

At the heart of contest strategy lies the concept of a contest log. It serves as your compass during the contest, helping you navigate the treacherous waters of problem-solving with precision and efficiency. The contest log is your strategic tool to optimize time management and prioritize tasks effectively.

To create a contest log, break down your contest time into 15-minute increments. At the end of each interval, record what you've been doing. These entries can be as simple as "thinking about P2" to indicate you were thinking about the second problem, "implementing P2" for coding the third problem, or "debugging P1" when looking for where your code goes wrong in the first problem.

Initially, some may find this task distracting, fearing it will disrupt their focus. However, the opposite is true. A few words won't significantly divert your concentration, but they will provide valuable insights. For instance, you might fall through the dangerous path of continuously saying “I’m so close!”, and tunnel vision on debugging. Without the contest log, you might unknowingly squander hours on a single problem.

Identifying Time Leaks

The contest log functions as a time leak detector. It reveals instances where you've unknowingly spent excessive time on a problem. During the excitement of a contest, it's easy to lose track of time. However, the contest log keeps you grounded, making you aware of time leaks that may have otherwise gone unnoticed.

By being conscious of how you allocate your time, you can make more informed decisions. Consider this scenario: you realize you've invested an hour and a half in debugging problem 2. With this awareness, you can choose to cut your losses and allocate the next 30 minutes to other problems. This strategic shift can be the difference between securing partial credit on multiple problems or being stuck in a debugging trench.

Leveraging Task Switching

An important part of a good content strategy is task switching. It involves periodically shifting your focus between different problems. This technique often leads to fresh insights and breakthroughs when you return to a problem after working on others.

To implement task switching effectively, set a rule for yourself: do not spend more than 30 minutes coding or debugging any single problem at the contest's outset. This ensures that you allocate time to every problem, giving you the opportunity to secure partial credit on each. This is especially important for the bronze, silver, and gold divisions, as the goal is to solve two to two and a half problems, emphasizing the significance of partial credits.

Incorporating task switching into your strategy can lead to remarkable results. It's not uncommon for students to return to a problem and suddenly grasp its solution after working on different tasks. The fresh perspective gained through task switching can be a game-changer.

Reading All Problems

Before immersing yourself in coding, invest a minute in reading all the problems thoroughly. While the temptation is strong to begin coding immediately, this approach can be counterproductive. Rushing into problem 1, assuming it's the easiest, might lead to frustration when you realize that it is actually the hardest problem.

By taking the time to read all the problems, you gain a holistic view of the contest. This approach allows you to identify the genuinely easiest problem. Ranking problems from easiest to hardest enables you to tackle the most manageable ones first.

Shortening Implementation Time

When solving problems, always keep in mind the split between the time you come up with the idea, and the time you take to implement. What should you do when you can come up with the ideas relatively quickly, but take many hours to implement, and even longer to debug? I discuss this issue specifically here.

How much time should you aim for?

For problems in the silver divisions and above, dedicating 40 minutes to thinking and 40 minutes to implementing and debugging is a good rule of thumb. This sums up to about 1 hour and 20 minutes per problem, making it feasible to tackle three problems in a contest within four hours. Keep in mind that the time required may vary for easier and more challenging problems, especially in Platinum.

Thus, spending 45 minutes on finding the idea is a good time. However, bronze students should aim to bring their implementation time down to at most 30 minutes, especially for bronze problems which tend to have shorter implementations. 

Tips for shortening implementation time

One way to achieve this is by organizing your code structure before you start coding. Have a clear idea of the sections, functions, and loops your code will include. This planning step can significantly reduce the time spent during implementation and debugging.

Additionally, if you find yourself stuck in debugging and your code is too long (e.g., over 40 lines for a bronze-level problem), consider simplifying sections of your code. Long, complex code is more prone to bugs. Condensing your code to less than 40 lines can often lead to the elimination of unidentifiable bugs. Higher-level competitors tend to code more concisely, so keeping your code clean and compact is a valuable skill.

Using a Debugger

Often, competitive programmers use simple print statements to debug their programs, and while this may be effective for shorter programs, as your code gets longer and longer, print statements can generate lots of confusion, slowing down the debugging process. To avoid losing time in this compartment, try using a debugger.

At its core, a debugger is a software tool designed to assist developers in finding and resolving bugs, glitches, and errors in their code. It provides a controlled environment where you can inspect the inner workings of your program, step through its execution line by line, and examine the values of variables at any given moment. While it might sound complex, debuggers are remarkably user-friendly and can drastically speed up the debugging process. For a comprehensive guide on how to use a debugger, check out Nathan’s video here.

Choosing Your Environment

For this tutorial, we'll be working with VSCode and Java. If you're using a different Integrated Development Environment (IDE) or text editor, the specifics might vary slightly, but the core functions remain the same. Debugging is all about understanding and controlling your code's execution.

Setting Breakpoints

Let's take a look at how to use a debugger effectively. We'll use a USACO Bronze problem from the 2020 February contest called "triangles" as an example. We won’t go into the specifics of the problem, so it’s fine if you aren’t familiar with it. Our goal is to understand how to use a debugger to ensure our code is running correctly.

A breakpoint is essentially a place in the code where we want to stop and check the current state of the variables, so we can see if any of the variables are not as we expected. We can set these breakpoints anywhere in the code. Then, when we debug, the debugger will run the program as normal, until it hits a breakpoint, when it then gives us full control.

Here, you can see that we define a breakpoint in line 15 by hovering to the left of the line number. In other IDEs, this may differ, but in general clicking around the line number will put a red dot, indicating a breakpoint.

The purpose of this breakpoint in line 15 is to check that the input has been properly read into our “points” array.

Once you’ve set breakpoints in all places where you want to check the state of the program, we can get to running the actual debugger.

Navigating the Debugger

To run the debugger in VS Code, simply go to the top right and click on the dropdown next to the run button, and select “Debug Java”.

If you cannot find this option in an IDE such as IntelliJ, try searching up how to run debug on your IDE.

Once you entered the debugger, your IDE will look something like this. It can be a bit overwhelming at first, but let’s explore everything that is going on.

Let's explore the debugger’s features:

• Highlighted Current Line: Line 15 is highlighted, indicating the current execution point.

• Variables Panel: This panel displays the values of all defined variables. For “triangles”, we can check if our points were read in correctly by expanding the "points" menu.

• Hover to Inspect: You can hover over variables in your code to see their current values. For example, hover over "N" to see its value.

Skipping Ahead

Suppose we want to program to continue executing. We can use this menu found at the top of the IDE:

This menu allows us to step forward by clicking on the second icon from the left. Stepping forward means allowing the program to continue its very next line of code, which can be incredibly helpful, as we often want to see how our variables change as the program progresses.

If you’re stuck in a loop, and don’t want to continuously click the “step forward” button, we can skip ahead in the code to a specific point. Define another breakpoint at the line that you want to stop at, and use the “continue” button, which is the first icon from the left.

Exploring Functions

Suppose we are at a line of code where a function is being called. Clicking “step over” will simply go to the next line, not giving us any information about what is going on inside this function.

To read the state of the program inside the function as well, we can use the “step into” feature, which is the 3rd button from the left, when on a line of code that calls a function. Now, you can inspect the variables and calculations happening within that function as well. Similarly, to exit the function, we can use the “step out” feature, which is the 4th button from the left, which goes back to the code that called the function.

Watching Variables

Oftentimes, you will have tons and tons of variables, so keeping track of each one you are interested in can be really tedious. This is solved by another powerful tool: the watch panel, which can be found on the bottom left under the variables panel.

If you click the “+” on the top right of the panel, you can add a variable or expression that you are interested in keeping track of. For example, in the “triangles” problem, we can add “points[i]” to the watch panel, and the debugger will tell us the value of points at index i at every point in time. You can even keep track of a specific property, such as “points[i].x”.

Conditional Breakpoints

Suppose we have a long loop, and we don’t care about every iteration of the loop, just certain iterations. We can use a conditional breakpoint to set this up. To set up a conditional breakpoint, add a breakpoint normally, right click it, and “edit breakpoint”.

Now, we can enter an expression to define when we want this breakpoint to activate, allowing us to only pause the program when we want to.

That covers the essential functions of a debugger that you need to know. Debugging can be a bit overwhelming at first, but with practice, you'll become more efficient at identifying and fixing issues in your code.

Post-Contest Analysis

Content strategy extends its influence beyond the contest itself. After the contest concludes, it's time for a thorough post-contest analysis. This phase is where you consolidate your learning and identify areas for improvement. Post-contest review is much more time-effective for learning than spending your time doing another practice contest instead, as you’ll just make the same mistakes again.

Review your contest log and reflect on your performance. Ask yourself critical questions. Did you allocate too much time to a specific problem? Could I have gotten a problem with better time management? Post-contest analysis serves as a diagnostic tool, revealing your strengths and weaknesses. If you have a coach or mentor, have them review it too, as they can point out things that you might not have thought was a mistake.

The goal of post-contest analysis is not just to dwell on your mistakes but to learn from them. It's an opportunity to fine-tune your strategy for future contests. The insights gained during this phase are invaluable, paving the way for continuous improvement.

Continuous Improvement

The sign of a successful contestant is their commitment to continuous improvement. To foster this growth, implement changes based on your post-contest analysis.

I often witness remarkable score improvements in students who diligently work on their content strategy. Thus, make it a rule to assess your content strategy after each contest; even a five-minute review can lead to significant score enhancements.

Platinum-Specific Strategies

As you progress to the platinum level, the dynamics of content strategy evolve. As the goal shifts more towards one and a half problems, the importance of partial credits becomes even more apparent.

Embrace Partial Scoring

Within Platinum contests, partial credit becomes even more important, as they can substantially boost your overall score. Imagine achieving 75% on one problem, 25% on another, and 25% on the third, which leads to almost one and a half problems already! Since you're not aiming for full solutions as often, allocate more time to partials. This approach can lead to a higher overall score, even if you don't complete any problems.

However, still shoot for the stars; whenever you can, aim for full solves. With proper preparation, you may find full solutions when thinking about how to solve the entire problem, or even if you don’t, you’ll have already found partial solutions without even knowing it.

Strategic Time Allocation

As always, managing time wisely is critical in all divisions, but it is especially important in Platinum, as you also have to balance going for full solves with going for partials. Begin with any problems that you might have the full idea for. Then, as you are nearing the end of the contest, focus on partials, balancing your time among the remaining problems. Time is a precious resource, especially in platinum contests, and should be allocated strategically.

Conclusion

As the upcoming USACO season approaches, remember that content strategy is your secret weapon. It can turn "I could have gotten that if I just had more time" into "I got it because I had a solid content strategy."

Maintain a contest log, organize code before implementing, use a debugger, embrace task switching, read all problems, and conduct post-contest analyses. These steps will significantly enhance your performance. For platinum participants, focus on partial scoring and strategic time allocation to maximize your points.

So, as you prepare for the upcoming contest, make content strategy and faster implementation/debugging a central part of your preparation. It's not just about coding faster but also about coding smarter. Effective content strategy can make all the difference in your journey to USACO success.

Thank you for reading, and best of luck in your USACO journey! May your contest log be your guiding star toward victory.

Nathan, a 4 time USACO Finalist and a USACO Guide developer, reveals how he prepared for USACO

Here’s the full video where I discuss the same content in detail: ”Nathan, a 4 time USACO Finalist and a USACO Guide developer, reveals how he prepared for USACO!"

I recently had the privilege of sitting down with Nathan Wang, a four-time USACO finalist and a USACO Guide developer. Today, we will delve into his remarkable journey through the world of competitive programming.

Introduction

Nathan Wang's journey through the world of competitive programming is nothing short of extraordinary. He has not only achieved the remarkable feat of becoming a four-time USACO finalist but is also a prominent figure within the USACO community. Beyond his impressive competitive achievements, Nathan has played a central role in the development of the USACO guide, a valuable resource for aspiring coders seeking to navigate the challenging waters of competitive programming. Nathan's story is a testament to dedication, passion, and the relentless pursuit of excellence in programming. 

Starting Out

Nathan's fascination with programming began long before he was introduced to USACO. He started programming at a young age, and by the time he reached seventh grade, he was already deeply involved in web development, which he did recreationally.

However, it was only in middle school that he stumbled upon USACO, thanks to his older brother. Intrigued, Nathan decided to participate in his first USACO contest. Surprisingly, his prior programming experience enabled him to excel. The bronze-level contests back then were not as challenging as they are today, which worked to Nathan's advantage. However, on his very first try, he managed to promote himself all the way to the gold level, which still demonstrated Nathan’s immense talent and impressive programming and problem-solving skills.

His Journey to Platinum

Nathan admitted that his journey from gold to platinum wasn't solely backed by rigorous study sessions. In fact, he attributed his advancement to a combination of luck and his foundational knowledge in programming. There was a particular contest where a problem was flawed, and Nathan was among those who managed to solve it before it was removed. This, combined with his scores from other problems, allowed him to advance, even though his solution wasn't entirely correct.

However, luck can only take one so far. Recognizing that he wasn't truly at a platinum level, Nathan decided to invest in his training. He enrolled in a summer program for USACO and honed his skills by solving numerous old USACO problems from the usaco.org website. He believed that continuous practice was key to acquiring the necessary skills to genuinely qualify for the platinum level.

Preparing for Camp

Transitioning from platinum to camp level required Nathan to immerse himself in rigorous practice sessions. He emphasized the importance of mastering foundational concepts like Dynamic Programming (DP) and other algorithms. Nathan’s strategy was straightforward – he tackled old USACO problems, with a focus on the gold and platinum problems to solidify his understanding. In fact, the summer before the season where Nathan went camp, he solved almost every single gold and platinum problem from past contests!

When going through the old problems, Nathan simply went down the list, from the oldest contests to the newest contests. However, one strategy I recommend employing when working on Platinum problems is to sort them based on the number of people who solved them. By reviewing the results, you could prioritize problems with the highest number of solutions first and gradually tackle those with fewer solutions. This method is not perfect, as the difficulty between contests could vary, but it provides a reasonable estimation.

Getting unstuck

Whenever Nathan confronted a problem he couldn't solve, he'd read the solution, ensuring he coded it himself to grasp the concept better. He would spend hours analyzing the often-cryptic solutions, and scour through the code again and again, trying to understand what it was really doing. If a problem was simply way too hard, he would give up and return at a later time. 

Nathan emphasized the importance of persistence, advocating for continuous effort unless one felt utterly stuck. For those who encounter frequent obstacles, he suggests leveraging resources like the USACO forum, a place where one can post questions and receive answers from others in the community. Asking others who are more experienced can really help you get unstuck or even help you see another perspective if you are unable to figure out a problem or understand a solution. 

In the end, Nathan’s priority was to enjoy the process and remain motivated. Participating in USACO was always a highlight for him. During the summer, he would sometimes spend entire weeks just preparing for it.

Nathan’s First Camp Experience

Upon qualifying, Nathan described his experience at the USACO camp as transformative. Before attending, he had considered his journey in competitive programming to be near its end. However, the camp reignited his passion. It was more than just about algorithms and contests; it was a social event. Nathan had a chance to connect with like-minded individuals, learn new concepts, and engage in fun activities like board games.

The camp organizers efficiently split the attendees into two groups – Guernseys and Holsteins. Guernseys consisted of the first-time campers, whereas Holsteins consisted of the returners, who were at camp to compete for a spot on the United States’ International Olympiad of Informatics team. This allowed for a more tailored experience. Nathan, being a Guernsey, had more time dedicated to learning and social activities, making his overall camp experience highly enjoyable, and even the best week of his life up to that point. 

Preparing to return

Returning to USACO camp as a Holsten is much more challenging than reaching camp for the first time, as you are competing to be a candidate for the IOI team. After his first year at camp, Nathan initially didn’t have many expectations and dreams - he was doing USACO and wanted to attend camp mostly for fun. 

However, during camp, a friend Nathan met at camp, who introduced him to a coach. This coach, offering a free service that aspiring competitive programmers could apply for, proved to be a game-changer for Nathan. Eager to seize this opportunity, he wasted no time in enlisting the coach's guidance.

The coach put together problem sets for Nathan to practice. The problem sets were carefully curated, primarily consisting of old Olympiad problems that closely mirrored the difficulty level of the hardest platinum-level USACO problems. The coach's knack for selecting problems that pushed Nathan's limits and providing clear, easy-to-understand solutions was instrumental in driving Nathan's progress.

One key attribute that set Nathan apart was his unwavering motivation. He understood that motivation was essential for continuous improvement. Whenever he encountered a particularly stubborn or frustrating problem, he had a unique approach. Instead of getting stuck for days on end without giving up, he would pivot to a different topic or problem sooner than most would. This strategy, driven by his desire to stay enthusiastic and maintain the joy of practicing, proved to be highly effective.

Nathan's relentless dedication, fueled by his motivating coach and his own intrinsic passion, ultimately paid off. Through his relentless efforts and determination, he secured his place at the USACO camp for a second time, returning as a Holstein.

Continuing to Prepare

At the highest levels of competitive programming, success hinges on one crucial factor: practice. It all boils down to who has devoted the most time and effort to solving a wide array of challenging problems. After mastering the essential algorithms and data structures that could potentially be encountered in competitions like the USACO, the real distinguishing factor becomes a contestant's problem-solving prowess.

Thus, between his second and third appearances at camp, Nathan similarly delved into a mix of old Olympiad-style problems, often under the guidance of the same trusted coach. This continuity in his training regimen allowed him to build on his existing foundation, refine his problem-solving strategies, and cultivate a deeper understanding of the intricacies of competitive programming.

Nathan’s Time Management

Finding time for USACO was never a challenge for Nathan. He never felt overwhelmed with schoolwork and didn't have many extracurricular commitments, as he focused all his energy on USACO. During summers, he opted out of summer programs, freeing up more time for preparation. Even during school hours, if a lecture wasn't captivating his attention, he would mentally work through problem statements he had read earlier. The benefit of this was that even without pen and paper, he could mull over a problem. It became a habit; whether he was eating dinner or in the shower, there was often a problem he was pondering over.

Others have shared similar experiences, bringing printed problems to class only to have them confiscated. But once you memorize the problem statement, no one can stop you from thinking about it. Of course, be sure to respect the teachers and their classes, but if you have a moment or two, why not problem solve?

The Long-term Value of USACO

Regarding summer activities, while many students feel pressured to join recognized summer camps or prioritize other extracurriculars, Nathan personally prioritized USACO. A key factor for him was seeing the long-term value in USACO. Even if he didn't make it to camp, the skills he honed would be invaluable during job searches or internships. Technical programming interviews become significantly easier with the preparation one gets from USACO. It felt like a win-win. Even if he didn't get selected for camp, the skills he gained would make future technical interviews a breeze.

Many have echoed this sentiment. A student mentioned that one of his college courses at Berkeley was primarily about algorithms and problem-solving, and thanks to his preparation, he breezed through it. This highlights USACO’s practicality as an extracurricular activity. While math competitions have their value, they often lack direct practical application. That's one reason Nathan transitioned from math competitions to computer science - advanced math wasn't as appealing to him, and he didn't see its direct practicality. With USACO, he felt he was investing his time wisely, especially since he enjoyed it more.

Furthermore, once you reach a certain division in USACO – whether that's platinum, gold, or silver, depending on your personal goals – you can take the next summer to relax a bit and focus on other extracurriculars. In the context of college admissions, once you achieve a division, you're there forever; you don’t need to maintain your skills. If you qualify for Platinum once, it's there for life, whereas with AMC or AIME, you must continuously qualify.

The USACO Guide

Nathan was in his second year when he started the USACO Guide. His motivation to create the guide stemmed from the existing training pages looking outdated, and wanting to modernize this excellent resource. The idea eventually evolved, and instead of just updating the old training pages, Nathan and his team decided to start from scratch, leading to the USACO guide. By creating his own resource, he had greater flexibility; he could move faster and iterate more quickly. The USACO guide provides a structured set of problems based on topics, making it easier for users to work on areas they're struggling with.

However, while it is called the USACO guide, why are most problems in the guide not from USACO? The goal of the USACO guide is to equip users with algorithms necessary for each division, and sometimes, these algorithms are best trained through repeated practice. Thus, doing additional practice outside of just USACO’s past problems is incredibly beneficial.

For the Platinum division, unlike the other divisions, there is a much more extensive range of topics. However, don’t be intimidated, as even Nathan didn’t memorize all the topics and algorithms. In fact, it is often more time efficient to practice topics that will come up more often, such as dynamic programming, rather than spending time learning obscure techniques that will rarely show up. For dynamic programming in particular, you can always get better and better at it, so it will always be time well spent to practice dynamic programming. 

In general, the USACO guide is meant to provide a foundational understanding, while your skills are meant to be developed through rigorous practice. It’s essential not to get demotivated if unfamiliar topics arise, and in general, prioritize dynamic programming since it's a versatile topic that frequently appears.

How to Most Effectively Use the USACO Guide

For those just starting out in a division, Nathan doesn’t recommend simply going down the list in the USACO Guide, doing all the problems in each category in order. This is because you lose out on vital problem-solving practice. By knowing which category of problems you are doing, you lose the need to come up with the fact that the problem uses that algorithm/data structure. For example, if you are in the “binary search” section of Silver, you automatically know the problems in that section use binary search, whereas in an actual contest, you will not have the information and might miss out on a problem you would otherwise be able to solve.

Instead, Nathan recommends 2 ways to effectively use the USACO Guide. The first way is applicable to those who are already proficient in most topics covered in a division; if there is a particular algorithm/data structure that you lack confidence in in your division, doing the targeted practice in the USACO guide can be incredibly useful and the most efficient way to practice.

The second way is applicable to those who are just starting out in a division. Before you jump right into a divisions’ problems, Nathan recommends learning all of the algorithms from the USACO Guide. Then, after you have a grasp of all the fundamental algorithms and data structures covered in the division, do practice on random problems from the past USACO contests. This avoids the tedious situation where you spend hours and hours on a problem, trying to figure it out, only to realize it simply uses a technique you have never seen before, but still ensures that you get practice in problem-solving. 

Nathan’s Advice for Those Preparing for USACO

Stay motivated. For Nathan, fun and enjoyment were paramount when solving USACO problems. He believes improvement is directly proportional to the number of problems you tackle. Rather than overthinking performance, focus on staying motivated and enjoying the learning process.

How You can Emulate Nathan’s Results

Nathan’s journey is defined by two major factors: repetition, and motivation. If you are able to solve thousands of problems while effectively learning from each and every one of them, you, too, will be able to accomplish what Nathan did. However, it is much easier said than done, so how do you do it?

First, repetition. Doing many practice problems and practice contests are the key to success in competitive programming.

• Where can I find all these practice problems? USACO barely has a few hundred!

  • Fortunately, Codeforces has a problem library of around ~10,000 problems that you can practice with. For the most effective practice, do problems with difficulties just above your skill level. To help choose problems, Codeforces allows you to filter the problem set for certain difficulties. As a general guideline, Bronze problems are around 800-1400, Silver problems are around 1500-2000, Gold problems are around 2100-2500, and Platinum problems are 2500+. However, you should try out the problems for yourself, and measure which difficulty is appropriate for you, regardless of division.

  • Codeforces aside, there are many other online competitive programming platforms that offer a versatile problem set, such as LeetCode and CSES for more standard problems, CodeChef and AtCoder for problems similar to Codeforces’ style, and online judges like oj.uz for Olympiad problems similar to USACO’s style.

  • Additionally, like Nathan, you could invest in a coach or an online course. These external resources are incredibly useful for not only helping you learn competitive programming, but also selecting appropriate problems, tailored to your current level.

• What about practice contests?

  • Many of the aforementioned online platforms offer amazing live contests. Codeforces, LeetCode, AtCoder, and CodeChef all offer contests at least once a week, which are great for practicing your problem solving skills under pressure. Furthermore, these sites have rating systems as well, allowing you to measure your progress and growth.

  • If you have leftover USACO problems that you have not looked at, doing a practice contest with those problems can often be the sole best way to practice. Emulate a contest setting and try your best to solve 3 problems from your division, and you can effectively measure where you are at.

• How do I find the time?

  • If you are truly dedicated to improving at competitive programming, you can always find the time to squeeze in an extra problem. Like mentioned, an effective way to create more time for problem solving that Nathan uses is to always have a problem in mind that you are thinking about. Read a few problem statements, and ponder these as you go through your day while doing monotonous activities.

Second, motivation. It’s easy to burn out doing competitive programming if you do thousands of problems in a short time period. How do you stay motivated, especially during the March-December period when there are no contests?

• One way to stay motivated is to participate in live contests on sites like Codeforces. Competing is always more exciting that just practicing, and while doing problems in a contest, 2, 3 hours can fly by quickly. Even practice contests are very effective, as a time limit will often push you to solve a problem, giving you more concentration. Also, seeing your rating grow on sites like Codeforces can also be a big motivator, as you know you are getting better.

• Another way to stay motivated that Nathan applied is to not get stuck on a problem for too long. Having a problem that you just cannot find the solution to no matter how many hours, days, weeks you spend on it can be incredibly demotivating, so it is often better to simply skip it. Of course, still spend sufficient time thinking about a problem before you skip it.

Conclusion

As you embark on your own journey in competitive programming, remember that every challenge you face is an opportunity for growth. Nathan's story is a testament to the power of persistence, dedication, and a genuine love for problem-solving. So, as you navigate the world of USACO, may his insights and experiences serve as an inspiration for your own path to success.

What is USACO Camp Like?

Here’s the full video where I discuss this in detail: What is USACO Camp Like?

Are you curious about what happens when the most skilled USACO competitors gather to learn and have fun? In this article, we'll take you on a journey through the USACO Camp experience. If you're searching for a unique blend of programming prowess, camaraderie, and memorable moments, you're in the right place.

USACO Camp Overview

USACO Camp stands as a prestigious training program, inviting the top 25 contestants from the Platinum division. Over the course of 10 intense days, participants immerse themselves in a world of learning and competition, with the ultimate goal of securing a spot on the International Olympiad of Informatics (IOI) team. The IOI is a global coding competition where the US has repeatedly excelled in.

Structure

USACO Camp divides participants into two distinct groups: the "Guernseys" and the "Holsteins." Guernseys are the first-time attendees hoping to learn and return as a Holstein, while Holsteins are veterans, and compete for a spot on the IOI team by participating in daily contests.

The exception to this are seniors, who are automatically placed in the Holstein category, as it is their final year to compete for a spot on the IOI team. Becoming a Holstein in your first year at camp is possible, but rare, and requires excellence in USACO’s Platinum contests as well as the USACO Camp contests.

The EGOI finalists follow a similar structure, where those attending camp for the first time are grouped with the Guernseys, and those returning are Holsteins and compete for a spot on the EGOI team. 

Fun Activities

While the heart of USACO Camp is coding, the experience extends far beyond the computer science. Participants create lasting friendships and enjoy a variety of extracurricular activities, including board games, chess, card games, and late-night movie marathons.

The camp even hosts relaxing events, such as mini-golf, ice cream parlor visits, push-up competitions, movie nights, white-water rafting, a trip to Six Flags, ultimate frisbee tournaments, and more. It's not just about coding; it's about connecting with like-minded individuals and creating unforgettable memories.

Guernseys have more leisure time as they primarily focus on classes, attending four lectures and two contests. However, Holsteins take on the pressure of daily contests, along with six lectures.

Further Exploration

 If you want a deeper look into USACO Camp, Melody's YouTube video offers an immersive perspective, showcasing various activities and daily life at Camp.

Conclusion

In summary, USACO Camp offers a remarkable blend of learning, competition, and, most importantly, fun. If the chance arises for you to attend, don't hesitate. It's an opportunity to create lifelong memories and advance your programming skills in an environment where like-minded peers share your passion. Don't miss the chance to experience the unforgettable USACO Camp journey.

How a Student Changed his Strategy to Ace USACO Bronze!

Here’s the full video where I discuss the same content in detail: How a Student Changed his Strategy to Ace USACO Bronze!

Hello, I'm Riya, and in this blog, I'm excited to delve into the strategies that transformed a former USACO bronze competitor's performance from average to perfect. In less than a month, this student went from struggling with bronze-level problems to acing the USACO bronze contest. I'll share the key strategies that led to this remarkable improvement.

Understanding the Challenge: 

Initially, our student had diligently solved every bronze-level problem during practice, but consistently fell short in the actual contests. The critical issue was his reliance on solutions for the harder problems. This common pitfall is discussed in more detail in one of my recent videos, which you can find here. The challenge lies in the fact that problems in the newer contests tend to be in the harder 30%, making it difficult to succeed if you're only comfortable with the older, easier problems.

Strategies for Success

Our primary goal was to strengthen the student's problem-solving skills. To achieve this, we devised a simple yet highly effective strategy. After working on a problem, if he couldn't solve it unaided, we encouraged him not to rush to the solution. Instead, we suggested taking a step back and dedicating 10-15 minutes to reflect on what the barrier was, and how he could get past it in the future. This approach turned out to be far more productive than mindlessly tackling more problems and significantly enhanced his problem-solving abilities.

Tracking Progress

One key tool we used was a Notion page (or a Google Sheet) to track all of the problems solved, marking the ones that required the solution to solve, which is a technique widely employed by top USACO finalists, composed of the top 25 Platinum contestants in the USA. The idea was to log what could have led to an independent solution, allowing the student to continually hone his problem-solving skills.

Expanding Problem Sets 

Our strategy didn't stop at reflection. To progress further, the student needed a broader range of problems to practice with. We went over how to select problems on Codeforces, emphasizing the importance of filtering for problems that match the current skill level. Then, when the student consistently solved these problems independently, we gradually increased the difficulty level. This approach significantly increased the difficulties of problems that he was able to solve without help, suggesting that this incremental process, through a large quantity of problems, had a substantial impact.

Speeding up the Observation Phase

One of the most crucial aspects we tackled was accelerating the observation phase. A powerful method we discussed was the following process: first, solve sample test cases by hand, carefully noting the process you used to solve them. Then, try to create test cases that your process/algorithm would fail at solving, and create a new algorithm to pass that test case, continuing this process until it's impossible to make your solution fail. This approach refines your problem-solving skills and guides you toward more efficient solutions. However, it's also vital to be aware of time limits, particularly when dealing with problems with tighter limits (where N is large).

Conclusion

These strategies were the most important and effective ones discussed in the original video with the student, which you can watch here. If you're committed to improving your USACO bronze score, I highly recommend watching the video and applying these techniques.

The Ultimate USACO Handbook: Strategies, Tips, and Insights

What is the USA Computing Olympiad?

The USA Computing Olympiad (USACO) is one of the most prestigious high school programming contests in the nation. It consists of a series of online programming contests  designed to identify and nurture talented high school students interested in computer science and algorithmic problem-solving. 

Why compete in USACO?

The main three benefits of competing in USACO are a boost to college applications, career advancement, and improving general problem-solving skills. For a comprehensive guide on how USACO can fit into your journey, check out one of our other blogs here.

1. Strengthening College Applications with USACO

Excelling in USACO competitions can significantly strengthen your college application. A majority of USACO Finalists end up attending MIT, and many others matriculate at top schools like Stanford, Harvard, and Princeton. Competitors who qualify for the Platinum or Gold division also tend to experience a significant boost to their college application.

2. Career Advancement through USACO Training

Technical software engineering job interviews often test the same concepts and skills as USACO does. Practicing USACO in high school means that you’ll have a head start in preparing for internship and job interviews after high school. Additionally, listing a strong USACO achievement on your resume can be helpful especially for recruitment from quantitative finance firms, which often look for former CS and Math olympiad competitors.

3. Developing Problem-Solving Skills via USACO

USACO helps you develop general problem solving skills, which can be applicable to any field or career you end up choosing.

How is USACO Structured?

USACO is divided into 4 divisions, with each division introducing more concepts and increasing in difficulty:

1. Bronze

2. Silver

3. Gold

4. Platinum

All participants begin in the Bronze division. Once they pass a certain score threshold in a contest, they are promoted to the Silver division. Participants remain in the Silver division until they reach Gold, where they compete to finally reach Platinum. There is never a risk of “demoting” to a lower division. 

Among competitors in the Platinum division, 16-24 of the best-performing students are invited to participate in the USACO Training Camp. Among these students, 4 students are ultimately selected to compete in the International Olympiad for Informatics (IOI). Additionally, 4-7 female-identifying students are invited to the training camp, where 4 of them will be selected to compete in the European Girl’s Olympiad in Informatics (EGOI). Participation in the EGOI or IOI is one of the most prestigious accomplishments that a high school student can achieve.

How do USACO Contests work?

Every season consists of four contests: the December Contest, January Contest, February Contest, and US Open. The US Open is typically held either during the end of March or beginning of April, and is considered the hardest contest. All contests are held on weekends from Friday to Monday, where competitors can choose to compete during any 4-hour time window they want (5 hours for the US Open).

Every contest has separate problem sets for each division. Each division presents three questions, each worth 333 points. Your score for a particular problem is calculated as 333 multiplied by the percentage of test cases you pass. If you manage to achieve a perfect score on all problems, you obtain a total score of 1000 and receive an in-contest promotion. For participants who don't attain a full score, those who score above a certain threshold (typically ranging from 700 to 800), announced after the contest, are promoted to the next division.

How Do I Register for USACO?

Students can register for an account on the official USACO website: http://usaco.org/. Once a student has created an account, they will be able to participate in all of the upcoming competitions.

How Do I Get Started?

There’s a lot of information as to where to begin, this video covers some great information for beginners. Alternatively, we also have a comprehensive blog post on the intricacies of getting started.

VPlanet’s Guide on Getting Started:

What Resources Should I Use?

A comprehensive list of resources available can be found on the USACO Resources Page. In general, the most effective resources for preparation are as follows:

• USACO Guide - A comprehensive guide authored by USACO Finalists. It includes topics to learn and problems to practice for each division.

• USACO Past Contests - Contains a list of all past contents and problems since 2012. 

• Codeforces - Offers a lot of competitive programming contests for additional practice outside of USACO.

• Free VPlanet Courses - Provides a categorized list of Codeforces problems for guided practice in each division beyond USACO questions.

Outside of the 4 core resources, other resources for learning include taking free online college algorithms courses, Youtube videos, and algorithms textbooks.

Can I Get Coaching From VPlanet Coding?

Yes you can! Once you know how to code, we have programs starting from USACO Bronze all the way up to USACO Platinum. If you’re super busy, then you need our program, so that you can advance faster and spend your time more efficiently. If you can get half your time back, then all those remaining hours can be spent on something else to make your college apps that much more competitive.

Here are 5 key benefits that we provide over other alternatives:

Comprehensive curriculum for each USACO division

VPlanet provides dozens of hours of video content with in-depth algorithms and problem walkthroughs, covering all the knowledge a student needs to know to become successful. Additionally, our curriculum teaches the essential problem-solving skills that are required beyond the knowledge of algorithms.

Carefully curated problems

Practicing on your own can be frustrating and inefficient. We know what it’s like to spend 2 hours thinking through a problem just to give up and read a solution you can barely understand. VPlanet has handpicked 100+ problems for each division, ensuring that the problems students work on are never too easy or too hard. We guarantee that each problem has just the right level of difficulty to optimize students’ improvement trajectory. 

Daily support from coaches

If students are ever stuck or confused, VPlanet provides daily support in the form of Facebook group discussions, Q&A, and one-on-one sessions with highly-experienced coaches. These sessions maintain a very small ratio between students and coaches to ensure that everyone receives as much personalized help as possible. 

In contrast, a typical USACO class can have as many as 30 students assigned to one teacher, with only 1-2 class sessions per week to ask for help. This class environment makes it difficult to ask for help and risks leaving many students behind.

Work at your own pace

An inevitable issue with USACO classes is that they fail to account for each student’s individual skill level. This issue guarantees that either a significant number of students are falling behind in class, or the class is too slow for many high-achieving students. VPlanet overcomes this issue, enabling students to go at the pace they want with regular support from coaches.

Advance faster through USACO

We find that VPlanet students tend to advance at a much faster pace than others. Our carefully crafted curriculum and sessions with coaches provides just the right amount of content and personalized support for students to improve as fast as possible. This leaves our students with more time to focus on other activities to strengthen their college applications.

What Programming Language Should I Compete With for USACO?

When you’re starting out in USACO’s Bronze division, compete with the language you’re most familiar with! After reaching Silver, however, it’s recommended that you use Java or C++ because Python can occasionally be too slow for certain problems. In Gold and Platinum, Java and C++ both remain great choices. However, after reaching USACO Camp, it’s recommended to switch to C++ because it’s the only supported language for the IOI.

For a comprehensive guide on getting started with USACO, check out our blog post here.

How do I advance from USACO Bronze to Silver?

Passing USACO’s Bronze division is doable for anyone with basic programming knowledge and solid problem solving skills. 

In terms of basic programming knowledge, a Bronze competitor needs to understand variables, control statements, loops, arrays, and recursion. Beyond understanding time complexity and how to use the built-in sort function, no additional algorithms knowledge is required to pass Bronze. However, knowing how to use basic data structures like dynamic lists, sets, and maps can often be helpful for a variety of problems.

The main challenge of passing Bronze is developing strong problem solving skills. Problem solving is not something that can be easily learned – it requires extensive practice. The best way to improve is to solve as many problems from past contests as possible. The newer contests are usually harder, so if you’re just starting out it’s recommended to start with the problems from the 2015-2016 contest season and gradually work your way to newer contests. The USACO Guide also provides a solid list of categorized problems with difficulty labels for more guided practice.

How do I advance from USACO Silver to Gold?

Passing USACO’s Silver division is not easy, but can be achieved through consistent learning and practice. Beyond the concepts covered in Bronze, Silver tests introductory algorithmic concepts and data structures. These include (but are not limited to):

• Binary search

• Ordered sets and maps

• Prefix sums

• Advanced recursion

• Graphs and graph traversals (depth-first search and breadth-first search)

• Floodfill

• Greedy algorithms

• Two pointer and sliding window techniques

Beyond knowledge of the above concepts, Silver also requires significantly stronger problem-solving skills. In Bronze, the most obvious brute force solution is typically sufficient to solve a problem. In Silver, however, the brute force solution almost never works, and it is up to the competitor to identify where repetitive work is being done and to leverage certain algorithms and data structures to increase efficiency. This problem-solving cannot be learned, and must be developed through consistent practice with past problems.

How do I advance from USACO Gold to Platinum?

After reaching USACO’s Gold division, competitors will already have developed strong problem solving skills. As such, the main differentiator between Silver and Gold problems is a strong conceptual understanding of more advanced algorithms and strong instincts on when each should be applied. Frequently tested algorithms and data structures include:

• Dynamic programming

• Shortest path algorithms (Djikstra’s, Bellman-Ford, Floyd-Warshall)

• Union Find

• Topological sort

• Minimum spanning tree algorithms (Kruksal’s, Prim’s)

• Segment trees / binary-indexed trees

• Combinatorics

USACO Success in a Time Crunch: Time-Saving Techniques for Busy High School Students

I used to think that advancing in USACO was impossible with my jam-packed schedule. However, I didn’t give up and kept trying different ways to make the best use of my time. Eventually, I came across several techniques that propelled me all the way to USACO camp, and today I want to share one of those techniques.

The first thing I did was I analyzed where all my time was going, and I found 3 areas that I was spending time on that weren't pushing me to my goals.

The first area was coding adjacent activities. Whenever I would go to Codeforces, I would instantly go down to the blog section and start reading the articles that show up there. While this was fun, reading blogs, even blogs related to coding, wasn’t what I needed to get to the next level. I needed to spend my time focusing on hard problems. Cutting out reading these blogs, browsing Quora, and checking discord gave me lots of time back.

The second area I saved time from was cutting out problems that are too easy. While it's important to start with problems that match your skill level, spending too much time on easy problems can eat into the time you could be using to work on more challenging ones. What I realized was that any problem I could solve easily by myself I would be able to solve in contest, so practicing on those problems is a waste of time. By focusing your efforts on problems that are just beyond your current level of expertise, you can learn new concepts and techniques while also building your problem-solving skills. This way, you can make the most of your study time and develop a more efficient approach to problem-solving, ultimately giving you an edge in the next USACO competition. So, challenge yourself and take on problems that stretch your abilities!

Now, be careful when avoiding problems that are too easy, because spending lots of time on problems that are too hard is also not the best use of time. In fact, the third area I saved time from was avoiding spending too much time on problems that are too difficult for me. While it's important to challenge yourself with tough problems, spending too much time on problems that are beyond your current level of expertise can be counterproductive. I was spending hours and hours on a problem and I was still stuck. Not only is this discouraging, I also didn’t learn as much from all that time as I could have learned.

By cutting out time from these 3 areas, I got so much time back that I didn’t stress about not having enough time ever again, even with a crazy high school schedule. You might be wondering that I’m saying don’t work on too easy problems or too hard problems, what did I end up doing?

I focused on problems that were just beyond my comfort zone - ones that you can solve with getting a few hints from the solution, and that allow you to learn new concepts and techniques. By using your time more effectively, you can make steady progress and build your problem-solving skills, all while avoiding the frustration and wasted time that comes with being stuck on a problem that is too hard for you, and avoiding the wasted time that comes with problems that are trivial for you. Be strategic in your problem selection and focus on the problems that will help you grow and develop as a USACO competitor and you might be surprised at what you can accomplish.

5 Common Mistakes That Competitors Make in USACO Bronze and Silver

Author: Nathan Gong

Throughout my personal experience of reaching the Platinum division and coaching dozens of students, I’ve come across a few mistakes that competitors (myself included) have been consistently making.

Here’s the full video discussing the same content in detail:

Mistake #1: Only practicing with topic lists

Popular sites like USACO Guide and Codeforces compile problems into different concepts. For example, on the USACO Guide, problems are divided into sections like depth-first search, prefix sums, and binary search.

The problem with practicing using these divided sections is that you already know what algorithm or data structure you're supposed to use before you even start solving a problem. This takes away a huge part of the problem-solving process, which is identifying the best algorithm to use in each situation. In a real contest, you won't be given this information, so it's crucial to practice under the same conditions. A great way to do this is to go through all the problems in the past contests section on the official USACO website. 

It's important to note that this doesn't mean you shouldn't use the USACO Guide or topic lists. The organization it provides is amazing for when you're starting out and trying to learn all the concepts tested in each division. However, once you feel comfortable with every concept, we recommend shifting your practice more to going through past contests.

Mistake #2: Emphasizing learning algorithms and data structures over getting better at problem-solving

In earlier divisions, having strong problem-solving skills is far more important than knowing a lot of algorithms and data structures. Generally, the only knowledge needed for Bronze is sorting, sets, and maps. And even then, you almost never need to actually implement any of these algorithms. As such, focusing your time on learning new algorithms will provide far less value than working on your problem solving abilities. You’re not going to pass a contest because you know how merge sort works. You’re passing it because you’ve built a deep understanding of how to apply sorting in a bunch of different situations. All of this applies to Silver as well, just make sure that you have concepts like binary search, graphs, depth-first search, and prefix sums down.

Mistake #3: Giving up Too Early

One common mistake that many people make during practice is that they’ll give up after just a few minutes of thinking in their head and not finding a solution. It’s crucial to spend at least 15-20 minutes thinking hard about the problem. Grab a piece of paper and sketch out examples or potential solution ideas to get better insights.

Only when you genuinely find yourself stuck and unable to progress after these 15-20 minutes should you resort to reading the editorial. Once you’ve understood the solution, it’s important that you implement the solution yourself without referring to the editorial code. Although it may seem like a waste of time, implementing the solution is key to make sure that you thoroughly understand how the problem works, and gives you further practice with something that you weren’t previously familiar with.

After you’re all done, take some time to reflect. If you weren’t able to solve the problem the first time around, think about what observations you missed out on that prevented you from getting to the solution. Also consider how you could’ve approached the problem differently such that you’d be able to make those observations the next time around.

Alternatively, if you managed to solve the problem, but it took a considerable amount of time, analyze where you spent the most time and think about how you could’ve been more efficient. This might involve writing more concise code, testing ideas before full implementation, or breaking down your solution into smaller parts.

Mistake #4: Poor Contest Strategy

During contests, a lot of competitors will start by reading through the first problem and jumping straight into implementation. This is almost always the incorrect approach. Contest problems are not ordered by difficulty, so you may very well be starting with the hardest question. Instead, you should read all problems before starting and tackle the easiest one first. 

When you’ve identified a solution for the problem you’re working on, make sure that it works before you start implementing. This means spending a few minutes coming up with test cases of your own (beyond the samples) and proving to yourself that the solution works. You don’t want to be an hour into implementation just to realize that your solution is completely wrong!

For more about contest strategy, I strongly recommend watching Riya’s video. The main idea of her video is to keep a contest log noting down what you’ve been working on every 15 minutes. Not only will it help you realize when you’ve spent too much time on one problem, but it will also help you analyze your time allocation and identify where you were inefficient after the contest is over.

Mistake #5: Debugging With Print Statements

This mistake is slightly controversial, but changing the way I debug has personally enabled me to find mistakes in my code much faster. While print statements are great for debugging smaller programs where there isn’t too much going on, they can often get overwhelming for more complex problems. For these cases, I strongly recommend learning to use the debug function in your IDE. Here’s a tutorial showing how to use a debugger: https://www.youtube.com/watch?v=x0yLsPX6tTY.

I hope you found at least one of these points helpful! By avoiding these mistakes, you should find your practice to be more efficient and your progress to be much faster. For me personally, recognizing and avoiding these mistakes have saved me a lot of time, helping me jump to Platinum within two contests after being stuck in Silver for an entire year.

How You Can Implement Solutions 5 Times Faster

Are you tired from the endless cycle of aimlessly fixing bugs in your solutions, only to be met with a sea of red “wrong answer” boxes slowly filling your screen? Solving USACO problems can be a time-consuming and downright frustrating experience, especially in the beginning.

One of our students, Diya, was struggling with this issue when she came to VPlanet. She explained how she would take over two hours to solve a problem, leaving her practice sessions inefficient and contests feeling like a race against the clock. After meeting with a coach, however, she learned techniques that changed how she tackled problems. By introducing better structure and organization, she eliminated the need to constantly go back and revise previous code. Within a week, Diya reduced implementation time down to just 25 minutes per problem! She also found herself dealing with significantly fewer bugs along the way. In the end, she was able to practice USACO much more efficiently and found it to be more enjoyable.

To achieve similar results as Diya, we recommend following four guidelines when solving USACO problems:

Plan your approach. Don’t start implementing until you have a fleshed-out solution. Figuring out the solution as you implement will often lead to a lengthy and convoluted program that’s hard to debug. Plus, you don’t want to find out that your solution doesn’t work halfway through! Once you have your idea, take a few minutes to plan out how you’ll implement it: write some broad pseudocode that outlines the steps your program takes to arrive at an answer. This way, you can structure your implementation process, making sure you’re not constantly jumping around but rather finishing one step at a time.

Break down your logic. Following from the previous guideline, instead of writing out the entire solution at once, think about how you can divide your code into smaller parts. You can achieve this by assigning each part to a method or by allocating specific sections within your code. This not only helps you stay organized but also makes the debugging process significantly easier. By breaking down your logic, you can test each part individually, allowing you to catch bugs more efficiently.

Analyze and debug. You should be regularly analyzing your code to make sure everything works as intended—don’t just wait until the very end! After writing out a piece of your logic, test it to make sure everything works before moving on. The sample case usually won’t be enough, so come up with your own tests and try to break your methods with edge cases. If you still end up getting wrong answers after writing out the entire solution, use your IDE’s debug tools or print statements to pinpoint exactly where something goes wrong. 

Reduce redundancies. Always think about if your code is as concise as possible. Any implementation over 150 lines long can almost always be reduced. If multiple parts of your code have similar functions, consider simplifying them. This could mean wrapping the repeated code in a method or condensing it using a loop—the way you refactor generally depends on the specific scenario you’re in. 

In conclusion, while solving USACO problems can sometimes be tedious and frustrating, employing the right implementation strategy will make the process more efficient and enjoyable. By incorporating the guidelines mentioned above, you can reduce time spent debugging convoluted code and staring at the dreaded wrong answer boxes. 

USACO: Closing the Gap Between Expectations with Reality

Here’s the full video where I discuss the same content in detail: USACO: Closing the Gap Between Expectations and Reality

The other day, I stumbled across a quote that really resonated with me:

“Don’t practice until you get something right, practice until you can’t get it wrong.”

I vividly remember my time in the Gold division when I was first learning dynamic programming (DP for short). Having solved a handful of practice problems from previous contests, I felt confident about my ability to solve DP problems in upcoming competitions. However, when the first contest arrived, I couldn’t solve a single problem. I still remember how devastated and demotivated I felt as I scrolled through the contest results, knowing that I failed to even come close to my expectations. Fortunately, months later, as I practiced more and more DP, I gradually began to solve more and more DP problems in contest until I promoted to the Platinum division. 

Reflecting on this experience, I realized that the issue wasn’t necessarily that I couldn’t solve the problems during contest; rather it was the disparity between my expectations and results. In hindsight, I had only managed to solve a couple easy practice problems, so why should I have expected to solve the more challenging problems in newer contests? It may seem foolish that I had set such lofty expectations, but I’ve seen many competitors struggling with this exact issue across every division and topic, whether it’s silver competitors overestimating their success with DFS problems or Gold competitors grappling with dynamic programming.

So, how can you bridge this gap between expectation and reality? Returning to the quote, instead of practicing until you get a few problems right, you should be practicing problems to the extent that you can’t get them wrong. While success can never be guaranteed, there's a level of proficiency you can attain where success becomes highly probable—most campers can solve any Gold DP problem, and most Platinum and Gold competitors can handle any problem in Bronze. The question then becomes: How can we determine the threshold we need to reach to confidently expect success in contests? Let’s draw a diagram, where let’s assume you’ve solved 50% of Gold DP problems in order by difficulty (this could apply to any topic or division):

At this stage, you can solve half of the problems, but you won't be able to solve any in a contest since the difficulty you can handle doesn't encompass the contest difficulty. This brings us back to the issue of expectations versus reality. Even if you've managed to solve half or a significant majority of practice problems, it’s unwise to anticipate solving the DP problem during contests. If you truly want to anticipate success, you need to practice until you reach this point:

By setting realistic expectations based on how much you’ve practiced, you’ll avoid disappointment from contest results. Naturally, the Gold division isn't solely comprised of DP problems, so to anticipate success, ensure that you thoroughly cover all the other common categories like Dijkstra's algorithm and Segment Trees. Again, this can be applied to any division and topic.

I hope you end up finding some of this advice helpful—it’s something that a lot of my students and I have learned throughout our experiences.