Many international students preparing for jobs in North America use LeetCode to practice coding problems. But a common question is: how exactly should you go about it? Just grinding from easy to hard problems isn’t very efficient, especially during a time-limited job search season. Choosing the right order to practice matters more than just the number of problems you solve. I made plenty of mistakes at first too, but eventually put together a route that works well for most people, focusing on understanding concepts rather than memorizing solutions.
At the very beginning, it’s best to get clear on fundamental data structures and algorithms — things like arrays, hash tables, and string manipulation, followed by common techniques like stacks, queues, binary search, and sliding windows. Easy and some Medium-level problems here are great for training your thinking, like classic Two Sum, Valid Parentheses, and Merge Two Sorted Lists. These types of problems often show up as the first question in interviews, so being comfortable with them is key.
Once you’ve got the basics down, move on to trees and graphs, including DFS, BFS, and both recursive and iterative approaches. Problems like binary tree traversals, maximum depth, and path sums test not only your algorithms but also your understanding of recursive call stacks. Graph problems can be tougher, but the most common ones (like Number of Islands or Course Schedule) only require you to solve a few well-chosen problems to grasp the core ideas.
Next, focus on classic high-frequency problems, mainly around array manipulation, dynamic programming (DP), and greedy algorithms. DP is usually the hardest part of interviews. Start with basic problems like Fibonacci and climbing stairs, then gradually move on to knapsack problems, longest common subsequence, and finally to more complex ones like edit distance and stock trading problems. At this stage, it’s crucial to summarize how to define states and state transitions — drawing diagrams and making tables really helps.
In the final phase, practice mock interview-style questions, focusing on problems frequently asked by companies like Facebook, Google, Amazon, and Microsoft. You can practice by tags or company-specific problem sets. I personally think mock interviews and whiteboard practice are essential, because even if your thinking is clear, if you can’t explain your ideas well, you’ll struggle in the real interview.
You don’t have to finish all the problems in one go. The key is to understand common patterns and improve your problem-solving skills. Interviewers care more about your thought process and communication than whether you’ve seen a specific question before. Find a pace that works for you and stick with it — that’s what really matters.
Release time:2025-05-16
