992. 恰好K个不同整数的子数组
Hard | Array, Hash Table, Sliding Window, Counting
Counting
594. 最长和谐子序列
Easy | Array, Hash Table, Sliding Window, Sorting, Counting
621. 任务调度器
Medium | Array, Hash Table, Greedy, Sorting, Heap (Priority Queue), Counting
347. 前 K 个高频元素
Medium | Array, Hash Table, Divide and Conquer, Sorting, Heap (Priority Queue), Bucket Sort, Counting, Quickselect
383. 赎金信
Easy | Hash Table, String, Counting
387. 字符串中的第一个唯一字符
Easy | Hash Table, String, Queue, Counting
451. 根据字符出现频率排序
Medium | Hash Table, String, Sorting, Heap (Priority Queue), Bucket Sort, Counting
169. 多数元素
Easy | Array, Hash Table, Divide and Conquer, Sorting, Counting
229. 多数元素 II
Medium | Array, Hash Table, Sorting, Counting
299. 猜数字游戏
Medium | Hash Table, String, Counting