Array

Medium | Array, Hash Table

Hard | Array, Binary Search, Greedy

Easy | Array

Medium | Array, Binary Search

Hard | Array, Binary Search, Segment Tree, Sweep Line

Medium | Array, Greedy, Sorting

Hard | Array, Dynamic Programming, Memoization, Matrix

Medium | Array, Greedy, Sorting, Heap (Priority Queue), Matrix

Hard | Array, Math, Binary Search, Geometry, Sorting

Easy | Array, Sorting, Counting