423. 从英文中重建数字
Medium | Hash Table, Math, String
Hash Table
424. 替换后的最长重复字符
Medium | Hash Table, String, Sliding Window
432. 全 O(1) 的数据结构
Hard | Hash Table, Linked List, Design, Doubly-Linked List
433. 最小基因变化
Medium | Hash Table, String, Breadth-First Search
438. 找到字符串中所有字母异位词
Medium | Hash Table, String, Sliding Window
442. 数组中重复的数据
Medium | Array, Hash Table, Sorting
448. 找到所有数组中消失的数字
Easy | Array, Hash Table
451. 根据字符出现频率排序
Medium | Hash Table, String, Sorting, Heap (Priority Queue), Bucket Sort, Counting
454. 四数相加 II
Medium | Array, Hash Table
457. 循环数组是否存在循环
Medium | Array, Hash Table, Two Pointers
460. LFU 缓存
Hard | Hash Table, Linked List, Design, Doubly-Linked List
1. 两数之和
Easy | Array, Hash Table
105. 从前序与中序遍历序列构造二叉树
Medium | Array, Hash Table, Divide and Conquer, Tree, Binary Tree
106. 从中序与后序遍历序列构造二叉树
Medium | Array, Hash Table, Divide and Conquer, Tree, Binary Tree
12. 整数转罗马数字
Medium | Hash Table, Math, String
128. 最长连续序列
Medium | Array, Hash Table, Union-Find
13. 罗马数字转整数
Easy | Hash Table, Math, String
133. 克隆图
Medium | Hash Table, Depth-First Search, Breadth-First Search, Graph Theory
138. 复制带随机指针的链表
Medium | Hash Table, Linked List
139. 单词拆分
Medium | Array, Hash Table, String, Dynamic Programming, Trie, Memoization