Interview Problems
Master classic coding interview problems with visual explanations. Each problem includes multiple approaches, complexity analysis, and common interview pitfalls.
What Are Interview Problems?
Interview problems are carefully crafted puzzles that test your ability to:
- Recognize patterns and constraints
- Choose the right data structure
- Optimize from brute force to optimal
- Communicate your thought process
Key insight: The best interviewees don't just solve problems—they explain their reasoning, discuss tradeoffs, and iterate toward better solutions.
Classic Problems
More interview problems coming soon. Each includes multiple approaches, visual walkthroughs, and interview strategies.
The Interview Strategy
Clarify
Ask about constraints, edge cases, and expected inputs. Never assume.
Brute Force First
Show understanding with a naive solution. This proves you can solve it.
Identify the Pattern
Look for two pointers, sliding window, stack, or DP opportunities.
Optimize & Code
Upgrade to the optimal solution and implement cleanly.
Meta Interview Questions
What if I can't solve the problem optimally?
That's okay. Interviewers want to see your thought process. Start with brute force, explain why it's suboptimal, and work toward improvements. Partial progress is better than silence.
Should I memorize solutions?
Memorize patterns, not solutions. If you understand why Two Pointers works for Trapping Rain Water, you can apply it to Container With Most Water and other problems.
How do I know which pattern to use?
Look at the constraints. Sorted array? Consider binary search. Need O(n) with O(1) space? Consider two pointers. Subarray/substring problems? Consider sliding window.
Myths vs Reality
You need to solve every problem in 15 minutes
Most interviews allow 30-45 minutes per problem. Use time to clarify and explain.
You must have the optimal solution immediately
Showing progression from naive to optimal demonstrates strong problem-solving skills.
Silence while thinking is bad
Narrating your thought process (even when stuck) shows reasoning ability.
LeetCode Hard problems are common
Most interviews focus on Medium problems with follow-up questions.