How to prep for LeetCode?

To effectively prepare for LeetCode and ace coding interviews, you’ll need a structured approach, practice, and consistency. Here's a step-by-step guide on how to prep for LeetCode:

1. Understand the Basics of Data Structures and Algorithms

Before diving into LeetCode problems, make sure you have a solid understanding of key data structures and algorithms:

• Data Structures: Arrays, Linked Lists, Stacks, Queues, Trees, Graphs, Hash Maps.
• Algorithms: Sorting, Searching, Recursion, Dynamic Programming, and Graph Traversals (DFS, BFS).

Resources:

• Books: Introduction to Algorithms by Cormen (CLRS), Cracking the Coding Interview by Gayle Laakmann McDowell.
• Courses: Take foundational courses on platforms like Coursera or Udemy to get an in-depth understanding.

2. Leverage LeetCode’s Explore Feature

LeetCode’s Explore feature provides curated problem sets that are ideal for structured learning. It allows you to focus on specific data structures or algorithms, guiding you through easy, medium, and hard problems in a logical progression.

• Start with Easy problems to gain confidence.
• Move on to Medium problems as you get comfortable with solving them.
• Tackle Hard problems once you have built the necessary problem-solving skills.

3. Focus on Problem-Solving Patterns

Recognizing problem-solving patterns helps you approach similar problems more efficiently. For instance:

• Sliding Window Pattern: Useful for array problems like finding subarrays.
• Two Pointers Pattern: Helpful for problems involving pairs or subarrays.
• DFS/BFS Pattern: Vital for tree and graph traversal problems.

Resource:

• Grokking the Coding Interview by DesignGurus.io is highly recommended by many for learning patterns.

4. Practice Regularly and Consistently

Consistency is key. Dedicate time each day to solving problems and improving your understanding.

• Daily Problem-Solving: Aim to solve 1–3 problems a day.
• Set Targets: Try to complete around 100–150 problems in a variety of topics before your interview.
• LeetCode Premium: If you’re preparing for specific companies, LeetCode Premium offers company-specific questions, allowing you to practice problems previously asked by companies like Google, Amazon, or Facebook.

5. Analyze and Learn from Solutions

After solving each problem:

• Review Your Solution: Check for mistakes or optimizations.
• Read Discussions: LeetCode’s discussion forums can offer multiple solutions, explanations, and approaches that might give you new insights.
• Time and Space Complexity: Make sure you understand the time and space complexity of your solution, and aim to improve it if possible.

6. Mock Interviews and Timed Practice

• Simulate Interviews: Set a timer when solving problems to simulate real interview pressure.
• Mock Interviews: Platforms like Pramp or DesignGurus.io offer mock interview experiences with real-time feedback. This helps in getting used to coding under time constraints.

7. Balance Between Theory and Practice

While practicing on LeetCode is important, don’t neglect the theory behind algorithms and data structures. Understanding the "why" behind algorithms helps in applying the right approach to solve problems.

8. Track Your Progress

Keep a log of the problems you’ve solved, especially those you struggled with. Revisit them periodically to ensure you’ve improved your approach. Tools like Notion, Google Sheets, or even LeetCode’s built-in tracking feature can help you keep organized.

Conclusion

Preparing for LeetCode requires a structured plan, consistent practice, and a balance between theory and problem-solving. Focus on building a solid understanding of data structures and algorithms, recognize patterns, and regularly solve problems to develop the skills needed for coding interviews. For those aiming for specific companies, utilizing LeetCode’s Premium service for company-specific questions is an excellent option.