Tips for Using LeetCode for Interview Preparation

Why Use LeetCode?

• Necessary for preparing for interviews at Big Tech companies (Amazon, Google, Microsoft)
• Not always required for startups

Choosing a Programming Language

• No specific language required; popular choices: C++, Java, Python, JavaScript
• Beginners should consider Python for its simplicity
• Stick to a language you are familiar with; understand basic syntax and concepts (loops, conditionals, functions)
• Spend time learning language-specific libraries and data structures (e.g. STL in C++)

Programming Language in Interviews

• Choice of language doesn’t matter as long as it's well-known
• Learn to solve problems using multiple languages
• Focus on a language you're comfortable with

Learning Data Structures and Algorithms

• Understand computer science fundamentals: time/space complexity, basic data structures, and algorithms
• Learn to calculate time/space complexity using Big O notation
• Familiarize with fundamental data structures (e.g. arrays, strings, binary trees)
• Study basic algorithms (e.g. sorting, searching, recursion)
• Resources: YouTube channel "William Fiset", books "Data Structures and Algorithms Made Easy" and "Cracking the Coding Interview"

Which LeetCode Problems to Solve?

• Start with problems by topic for deeper understanding
• Begin with easy problems, then progress to medium
• Focus more on medium problems as they're common in interviews
• Avoid hard problems at the beginning

Number of Problems to Solve

• Subjective; if new, aim for 300-400 problems
• Focus on learning from each problem instead of increasing problem count
• Enjoy the process; leads to higher problem count

Problem-Solving Approach

• Understand the problem statement and expected input/output
• Start with brute force solution and optimize
• Plan before coding; understand time/space complexity
• Test your code, including edge cases

When to Look at Solutions

• Spend 30-60 minutes on a problem before looking at hints/solutions
• Understand the solution and try to implement it yourself
• Mark difficult problems for revision and revisit them later

Solving More Problems in Less Time

• Learn and recognize problem-solving patterns
• Apply the same approach to similar problems

Memorizing Solutions

• Don’t memorize; focus on understanding the problem-solving process
• Explanation of thought process is crucial during interviews

Practicing in Interview-like Conditions

• Practice in a timed environment (use extensions like LeetCode Timer)
• Participate in LeetCode contests for timed practice

LeetCode Premium

• Not necessary for beginners
• Benefits of premium: access to premium problems, company-specific problems, visual solutions