Algorithm Interview Questions
Algorithm questions test your problem-solving ability under pressure. Interviewers aren't just looking for the right answer — they want to see how you break down problems, analyze tradeoffs, and optimize. These questions cover the patterns that appear most frequently: sliding window, two pointers, dynamic programming, and graph algorithms. Understanding the pattern is more valuable than memorizing individual solutions.
Fundamentals
Big O Notation — Time and Space Complexity Explained
Explain Big O notation. How do you determine the time and space complexity of an algorithm?
Sorting Algorithms Compared — When to Use Which
Compare quicksort, merge sort, and heap sort. When would you choose each one?
Patterns
Two Pointer Technique — Algorithm Pattern for Interviews
What is the two pointer technique? Give examples of problems where it's useful.
Sliding Window Pattern — Solving Subarray Problems Efficiently
What is the sliding window technique? When do you use a fixed vs. variable window?
Dynamic Programming — How to Approach DP Interview Problems
How do you approach a dynamic programming problem? Walk me through your framework.