How long to prep for LeetCode?

The time required to effectively prepare for LeetCode depends on your current skill level, goals, and the difficulty of the interviews or coding challenges you are aiming to conquer. Whether you’re preparing for a coding interview, improving your problem-solving skills, or aiming to master algorithms and data structures, here's a breakdown of how long it typically takes to prep for LeetCode.

1. Determining Factors for Prep Time

a. Experience Level

• Beginner: Little to no experience with algorithms, data structures, or coding interview prep.
• Intermediate: Familiar with common algorithms and data structures but needs to improve problem-solving speed and efficiency.
• Advanced: Experienced in solving algorithmic problems and comfortable with most data structures but needs practice with hard problems or specialized topics.

b. Goal and Target Companies

• General Skill Improvement: If your goal is to improve your overall problem-solving skills and understanding of algorithms and data structures, the timeline might be more flexible.
• Coding Interview Preparation: Preparing for interviews at FAANG or similar companies can take longer due to the complexity of problems asked. Some companies specifically ask LeetCode Medium and Hard problems.
• Competitive Programming: If you're aiming for competitive programming, expect a more extensive and rigorous timeline, since competitive problems often go beyond typical LeetCode problems.

2. Suggested Prep Time Based on Experience

a. Beginners (3 to 6 Months)

If you're new to coding interviews and algorithms, you’ll need a solid foundation. Here's how a beginner might prepare:

• Learning Algorithms and Data Structures (1-2 Months):

  • Learn key concepts like arrays, strings, linked lists, binary trees, hash maps, sorting algorithms, and recursion.
  • Recommended resources: introductory courses or books like "Cracking the Coding Interview."

• Practicing Easy Problems (1 Month):

  • Focus on Easy LeetCode problems to build problem-solving confidence and reinforce your understanding of basic algorithms and data structures.
  • Aim to solve at least 3-5 problems per day.

• Moving to Medium Problems (2 Months):

  • Once comfortable with Easy problems, transition to Medium LeetCode problems.
  • Spend time understanding concepts like dynamic programming, depth-first search (DFS), breadth-first search (BFS), and sliding windows.

• Advanced Topics and Hard Problems (1 Month):

  • After gaining confidence, start attempting Hard problems. Focus on topics like graph algorithms, dynamic programming optimization, and advanced tree problems.
  • This will prepare you for higher-level coding interviews or more challenging roles.

b. Intermediate (2 to 3 Months)

If you already have a foundation in algorithms and data structures but need to improve efficiency and speed:

• Revise Fundamentals (1 Month):

  • Start by revisiting core topics like arrays, linked lists, binary trees, and basic dynamic programming.
  • Work through Easy and some Medium LeetCode problems to refresh key concepts.

• Focus on Medium Problems (1-2 Months):

  • Dedicate the majority of your prep time to Medium problems, as they make up the bulk of interview questions in companies like Google, Facebook, and Amazon.
  • Solve at least 5-7 problems per day while focusing on time and space complexity optimization.

• Attempt Hard Problems (Final Weeks):

  • In the last few weeks of your prep, focus on Hard problems to sharpen your skills in advanced topics like backtracking, bit manipulation, and complex graph traversal.

c. Advanced (1 Month or Less)

If you're already experienced in competitive programming or have strong algorithmic skills, you’ll likely need less time to prepare:

• Focus on Medium and Hard Problems (1 Month):

  • Spend most of your time on Medium and Hard problems to fine-tune your skills and solve efficiently under time pressure.
  • Target companies like Google, Facebook, or other top tech firms often use these harder problem types.
  • Solve 8-10 problems per day, focusing on optimization techniques and edge cases.

• Mock Interviews (Last 2 Weeks):

  • In the final phase of preparation, focus on mock interviews using platforms like Pramp or LeetCode Premium’s mock interview feature. Simulate real interview conditions and time constraints.

3. Daily Practice Plan

To get the most out of your prep time, it’s essential to establish a routine. Here’s a sample plan:

• Daily Routine:
  • Morning: Review a core concept or algorithm (e.g., dynamic programming, graph algorithms).
  • Midday: Solve 2-3 LeetCode problems (start with Easy, move to Medium).
  • Afternoon: Review solutions, optimize code, and analyze time and space complexity.
  • Evening: Attempt 1 harder problem or review alternative solutions from the LeetCode Discuss section.

4. Resources to Accelerate Learning

• Courses:

  • Grokking the Coding Interview: Patterns for Coding Questions (Best for learning common coding patterns).
  • Grokking Data Structures & Algorithms for Coding Interviews.

• Books:

  • "Cracking the Coding Interview" by Gayle Laakmann McDowell.
  • "Elements of Programming Interviews" by Adnan Aziz.

• Mock Interviews:

  • Use platforms like Pramp, LeetCode Premium, or DesignGurus.io to simulate real interview conditions and get feedback.

5. Final Thoughts: Tailoring Prep to Your Schedule

The time required to prepare for LeetCode ultimately depends on how much time you can dedicate daily, your current proficiency, and the complexity of the jobs or companies you're targeting. Whether you’re starting from scratch or brushing up on advanced concepts, consistent and targeted practice is the key to mastering LeetCode problems.

• Beginner: 3-6 months
• Intermediate: 2-3 months
• Advanced: 1-2 months or less

By building a structured plan and staying consistent with practice, you can be well-prepared for coding interviews and solve a wide range of LeetCode problems confidently.