Top DSA Patterns You Must Know for Coding Interviews

You do not need to memorize every problem. You need to recognize patterns.

1. Two Pointers

Useful for sorted arrays, palindrome checks, and pair problems.

2. Sliding Window

Useful for substring, subarray, and variable-length optimization problems.

3. Hash Map

Useful when you need constant-time lookups or frequency tracking.

4. Prefix Sum

Useful for range sums and cumulative transformations.

5. Binary Search

Useful not only on arrays, but also on answers.

6. DFS and BFS

Essential for trees, graphs, grids, and traversal-based reasoning.

Final advice

When you solve a problem, always ask: which reusable pattern did this belong to?