How to Use LeetCode Efficiently: A Complete Guide for Beginners and Intermediates

In the competitive world of tech and software engineering, coding interviews are often the gateway to high-paying jobs at companies like Google, Amazon, Facebook, and Microsoft. One of the most popular platforms for interview preparation is LeetCode—a vast repository of coding problems categorized by difficulty, topic, and company.

However, simply solving problems at random on LeetCode can feel overwhelming and inefficient. Whether you’re just getting started or trying to get more out of your practice sessions, this guide will walk you through how to use LeetCode efficiently so that your hard work pays off.

Why Use LeetCode?

Before diving into strategy, it's essential to understand why LeetCode is so popular among developers:

1. Real interview questions from top tech companies

2. A variety of problem categories (arrays, strings, trees, etc.)

3. Features like contests, discussion forums, and study plans

4. Support for multiple programming languages

5. In-browser code editor with instant feedback

But despite these features, many users get stuck or burn out without seeing progress. The key is to practice smart, not just hard.

Step 1: Define Your Goal

Your approach to LeetCode will depend heavily on your goal. Are you:

1. Preparing for coding interviews?

2. Trying to improve problem-solving skills?

3. Practicing for competitive programming?

4. Switching from a non-tech role to software engineering?

If your primary goal is interview preparation, your focus should be on mastering core data structures and algorithms, not solving every single problem on the site.

Step 2: Choose a Study Plan

LeetCode offers curated study plans tailored to your goals, such as:

1. Top Interview 150

2. 75 Must Do

3. SQL or Database-specific plans

4. Company-specific prep (Google, Amazon, etc.)

These plans help you avoid decision fatigue and maintain consistency. Stick to one plan instead of hopping between random problems.

Step 3: Follow the 3-Pass Rule

Solving a problem once and moving on rarely helps with long-term retention. Here's a 3-pass strategy:

First Pass – Try to Solve It Yourself (30–45 minutes)

Read the problem carefully, understand constraints, and try solving it without looking at solutions. Even if you fail, you’ll gain an understanding of what's missing.

Second Pass – Study and Reimplement the Optimal Solution

Read the official solution or a highly upvoted community answer. Then rewrite the solution from scratch without copy-pasting. Focus on understanding why each step works.

Third Pass – Revisit After a Few Days

Return to the problem in 3–7 days. Try solving it again from memory. If you still struggle, that’s a signal to study the concept further.

Step 4: Focus on Patterns, Not Just Problems

Top candidates don’t memorize hundreds of problems—they recognize problem-solving patterns.

For example:

1. Two pointers: Used in problems involving sorted arrays or linked lists.

2. Sliding window: Useful in subarray or substring problems.

3. Backtracking: Core to problems like permutations and combinations.

4. Binary search: Works on sorted datasets or search problems.

5. Dynamic programming (DP): Applies to overlapping subproblem scenarios.

Once you recognize these patterns, solving new problems becomes easier and faster.

                                              

Step 5: Master the Essentials First

For most interviews, you don’t need to dive deep into obscure topics like segment trees or suffix arrays. Focus first on these essential topics:

1. Arrays & Strings

2. Hash Maps & Sets

3. Stacks & Queues

4. Linked Lists

5. Trees (Binary Tree, BST)

6. Recursion & Backtracking

7. Dynamic Programming

8. Sorting & Searching

9. Graphs (BFS, DFS basics)

Spend extra time on DP and Trees, as these tend to be common and tricky.

Step 6: Track Your Progress

Don’t just solve and forget. Use spreadsheets or tools like Notion, Obsidian, or LeetCode’s own bookmark and notes feature to:

1. Track which problems you’ve solved

2. Mark ones you struggled with

3. Tag problems by topic and difficulty

4. Note key takeaways or optimized solutions

This creates a personalized revision sheet you can use later before interviews.

Step 7: Don’t Ignore Time and Space Complexity

Getting the correct output isn’t enough. Interviewers care deeply about how you optimize for:

1. Time complexity: How does performance scale with input size?

2. Space complexity: Are you using memory efficiently?

Always write down and analyze the Big O for your solutions, even if LeetCode doesn't require it.

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Step 8: Simulate Real Interviews

Practicing under pressure is critical. Try these methods:

1. LeetCode mock interviews: Timed questions simulating real interviews.

2. Time-boxing: Solve problems within 30-45 minutes.

3. Peer practice: Pair with a friend to do mock interviews.

Additionally, consider platforms like Pramp or Interviewing.io for live mock interviews with peers or engineers.

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Step 9: Engage with the Community

LeetCode’s discussion forum is gold for learning:

1. Find different solution approaches

2. Learn trade-offs between iterative vs recursive strategies

3. Read about real interview experiences

4. Ask questions if you're stuck

Commenting and discussing can reinforce your understanding and build confidence.

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Step 10: Avoid Burnout

LeetCode grind is real, and it can be exhausting. Here’s how to stay sane:

1. Take breaks: Follow a 5–2 schedule (5 days study, 2 days rest).

2. Mix easy, medium, and hard problems.

3. Celebrate small wins: Every bug fixed is a learning point.

4. Balance practice with system design and behavioral interview prep.

Consistency beats intensity in the long run.

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Pro Tips for Efficiency

1. Sort problems by frequency to prioritize popular ones.

2. Use tags and filters to group by company or topic.

3. Use LeetCode Premium if you're preparing for FAANG-level roles—it gives access to company-specific problems.

4. Revise weekly: Redo 5–10 problems you struggled with the most.

Final Thoughts

LeetCode is a powerful tool—but like any tool, its impact depends on how you use it. By setting clear goals, following structured plans, and practicing mindfully, you can dramatically cut down your preparation time while maximizing results.

Remember, the goal is not to memorize 500 solutions—it’s to understand how to break problems down, spot patterns, and think like an engineer. Use LeetCode efficiently, and you’ll not only ace interviews but also become a stronger developer.