1830. 使字符串有序的最少操作次数
Hard | Hash Table, Math, String, Combinatorics, Counting
Hash Table
1832. 检查句子是否为全字母句
Easy | Hash Table, String
1857. 有向图中最大颜色值
Hard | Hash Table, String, Dynamic Programming, Graph Theory, Topological Sort, Memoization, Counting
1865. 寻找特定和的数对
Medium | Array, Hash Table, Design
1876. 长度为三的不同字符子串
Easy | Hash Table, String, Sliding Window, Counting
1893. 检查是否所有整数都被数组覆盖
Easy | Array, Hash Table, Prefix Sum
1897. 重新分配字符使所有字符串都相等
Easy | Hash Table, String, Counting
1912. 设计电影租赁系统
Hard | Array, Hash Table, Design, Heap (Priority Queue), Ordered Set
1930. 长度为3的唯一回文子序列
Medium | Hash Table, String, Bit Manipulation, Prefix Sum
1932. 合并多个二叉搜索树
Hard | Array, Hash Table, Tree, Depth-First Search, Binary Search Tree, Binary Tree