DSA: Topic 2: Hash Maps & Sets

Technical interviews frequently test three key DSA patterns. Hash Maps, implemented as dictionaries in Python, optimize runtime to O(1) by trading memory to avoid nested loops. The Two Pointers technique uses two indices to solve pair problems or handle sorted arrays. Meanwhile, the Sliding Window pattern is essential for contiguous subarray or substring problems involving maximum or minimum values. Mastering these patterns allows candidates to optimize O(n²) solutions and recognize efficient algorithmic approaches.