Design

Hard | Array, String, Design, Trie, Data Stream

Medium | Array, Hash Table, Binary Search, Design

Hard | Array, Binary Search, Design, Binary Indexed Tree, Segment Tree

Hard | Hash Table, Stack, Design, Heap (Priority Queue)

Hard | Linked List, Design

Medium | Hash Table, Tree, Depth-First Search, Breadth-First Search, Design, Binary Tree

Medium | Array, Binary Search, Design, Segment Tree, Ordered Set

Medium | Array, Binary Search, Design, Segment Tree, Prefix Sum, Ordered Set

Hard | Binary Search, Design, Segment Tree, Prefix Sum, Ordered Set

Medium | Design, Heap (Priority Queue), Ordered Set