Design.md

Design

Easy

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155. Min Stack
225. Implement Stack using Queues
705. Design HashSet
706. Design HashMap

Medium

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146. LRU Cache
173. Binary Search Tree Iterator
208. Implement Trie (Prefix Tree)
211. Design Add and Search Words Data Structure
284. Peeking Iterator
304. Range Sum Query 2D - Immutable
341. Flatten Nested List Iterator
355. Design Twitter
380. Insert Delete GetRandom O(1)
382. Linked List Random Node
384. Shuffle an Array
535. Encode and Decode TinyURL

Hard

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297. Serialize and Deserialize Binary Tree
381. Insert Delete GetRandom O(1) - Duplicates allowed