LeetCode Q&A: Hash Maps
HashMap and HashSet problem solving
Easy
15 problems
Medium
25 problems
Hard
8 problems
Common Hash Maps Patterns
When to Use
- Frequency counting
- Finding duplicates
- Group by operations
- Two sum problems
Common Patterns
- HashMap + Array
- Two HashMaps
- HashMap + Sliding Window
- Prefix sum with HashMap
Coming Soon
Detailed solutions with multiple approaches, time/space complexity analysis, and video explanations.