# 目录

Number

Problems

Difficulty

Topics(Tags)

1 Two Sum 两数之和等于一个输入的数 Easy Array, Hash Table
3 Longest Substring Without Repeating Characters 子字符串的最大不重复长度 Medium Hash Table, Two Pointers, String
4 Median of Two Sorted Arrays两个数组的中位数 Hard Array, Binary Search, Divide and Conquer
5 Longest Palindromic Substring 最长回文子字符串 Medium String, Dynamic Programming
6 ZigZag Conversion 之子形转换字符串 Medium String
7 Reverse Integer 翻转整数 Easy Math
8 String to Integer Atoi 把字符串转换成整数 Medium String, Math
9 Palindrome Number 验证回文数字 Easy Math
10 Regular Expression Matching 正则表达式匹配 Hard String, Dynamic Programming, Backtracking
11 Container With Most Water 装最多水的容器 Medium Array, Hash Table
12 Integer to Roman 整数转罗马数字 Medium String, Math
13 Roman to Integer 罗马数字转化成整数 Easy String, Math
14 Longest Common Prefix 最长共同前缀 Easy String
15 3Sum 三数之和 Medium Array, Two Pointers
16 3Sum Closest 最近三数之和 Medium Array, Two Pointers
17 Letter Combinations of a Phone Number 电话号码的字母组合 Medium String, Backtracking, DFS
18 4Sum 四数之和 Medium Array, Hash Table, Two Pointers
19 Remove Nth Node From End of List 移除链表倒数第N个节点 Medium Linked List, Two Pointers
20 Valid Parentheses 验证括号 Easy String, Stack
21 Merge Two Sorted Lists 混合插入有序链表 Easy Linked List
22 Generate Parentheses 生成括号 Medium String, Backtracking, DFS
23 Merge K Sorted Lists 合并k个有序链表 Hard Linked List, Divide and Conquer, Heap
24 Swap Nodes in Pairs 成对交换节点 Medium Linked List
25 Reverse Nodes in K Group 每k个一组翻转链表 Hard Linked List
26 Remove Duplicates From Sorted Array 有序数组中去除重复项 Easy Array, Two Pointers
27 Remove Element 移除元素 Easy Array, Two Pointers
28 Implement strStr() 实现strStr()函数 Easy Two Pointers, String
29 Divide Two Integers 两数相除 Medium Math , Binary Search
30 Substring With Concatenation of All Words 串联所有单词的子串 Hard Hash Table, Two Pointers, String
31 Next Permutation 下一个排列 Medium Array
32 Longest Valid Parentheses 最长有效括号 Hard String, Dynamic Programming
33 Search in Rotated Sorted Array 在旋转有序数组中搜索 Medium Array, Binary Search
34 Search for a Range 搜索一个范围 Medium Array, Binary Search
35 Search Insert Position 搜索插入位置 Easy Array, Binary Search
36 Valid Sudoku 验证数独 Medium Hash Table
37 Sudoku Solver 求数独的一个解 Hard Backtracking,Hash Table
38 Count and Say 计数和读法 Easy String
39 Combination Sum 组合之和 Medium Array, Backtracking
40 Combination Sum II 组合之和之二 Medium Array, Backtracking
41 First Missing Positive 首个缺失的正数 Hard Array
42 Trapping Rain Water 收集雨水 Hard Array, Two Pointers, Stack
43 Multiply Strings 字符串相乘 Medium String, Math
44 Wildcard Matching 通配符匹配 Hard Math, Dynamic Programming, Backtracking, Greedy
45 Jump Game 2 跳跃游戏2 Hard Array, Greedy
46 Permutations 全排列 Medium Backtracking
47 PermutationsII 全排列2 Medium Backtracking
48 Rotate Image 旋转图像 Medium Array
49 Group Anagrams 群组错位词 Medium String,Hash Table
50 Pow(x, n) 求x的n次方 Medium Math, Binary Search
51 N Queens N皇后问题 Hard Backtracking
52 N Queens II N皇后问题之二 Hard Backtracking
146 LRU Cache 最近最少使用置换缓存器 Hard Design