一、数学问题
Easy
7. Reverse Integer [Easy]
172. Factorial Trailing Zeroes [Easy] 阶乘有几个0
263-264. Ugly Number I & II [Easy & Medium] 丑数系列
278. First Bad Version [Easy] 二分查找
509. Fibonacci Number [Easy] 斐波纳切
Medium
165. Compare Version Numbers [Medium] 版本比较
179. Largest Number [Medium] 字符串排序
223. Rectangle Area [Medium] 图形面积题
319. Bulb Switcher [Medium] 数学题
357. Count Numbers with Unique Digits [Medium] 数学
372. Super Pow [Medium] 数学
621. Task Scheduler [Medium] 数学
Hard
二、数组
Easy
1-15-18-454. 234Sum [Easy & Medium] Sum系列问题
27. Remove Element [Easy] 数组移动
121-123. Best Time to Buy and Sell Stock I & II & III [Easy & Hard] 买卖股票
136-137. Single Number I & II [Easy] 位运算
167. Two Sum II - Input array is sorted [Easy]
189. Rotate Array [Easy] 数组
209. Minimum Size Subarray Sum [Medium] 子区间
605. Can Place Flowers [Easy] 数组/隔0放1
Medium
75. Sort Colors [Medium] 快排
153-154. Find Minimum in Rotated Sorted Array I & II [Medium & Hard] 二分查找
162. Find Peak Element [Medium] 二分查找
274-275. H-Index I & II [Medium] 数组
287. Find the Duplicate Number [Medium] 1-n找重复
299. Bulls and Cows [Medium] 数组
300. Longest Increasing Subsequence [Medium] 二分查找
398. Random Pick Index [Medium] 随机数
609. Find Duplicate File in System [Medium] 用到字典
611. Valid Triangle Number [Medium] 数组
1052. Grumpy Bookstore Owner [Medium] 滑动窗口
1094. Car Pooling [Medium] 汽车载人
Hard
*76. Minimum Window Substring [Hard] 滑动窗口
295. Find Median from Data Stream [Hard] 大顶堆和小顶堆
三、字符串
Easy
12-13. Roman and Integer [Medium & Easy] 罗马和数字转换
38. Count and Say [Easy]
67. Add Binary [Easy] 加法
409. Longest Palindrome [Easy] 最长回文
521. Longest Uncommon Subsequence I & II [Easy & Medium]
925. Long Pressed Name [Easy] 字符串
Medium
3. Longest Substring Without Repeating Characters [Medium] 滑动窗口
5. Longest Palindromic Substring [Medium] 最长回文
131. Palindrome Partitioning I & II [Medium & Hard] DP/回溯
516. Longest Palindromic Subsequence [Medium] DP最长回文
Hard
四、树
Easy
104. Maximum Depth of Binary Tree [Easy] 递归/BFS
108. Convert Sorted Array to Binary Search Tree [Easy] 树
110. Balanced Binary Tree [Easy] 平衡树/递归
112-113. Path Sum I & II [Easy & Medium] 递归和DFS
235-236. Lowest Common Ancestor of a Binary Search Tree [Easy & Medium] 最小父节点
257. Binary Tree Paths [Easy] DFS
501. Find Mode in Binary Search Tree [Easy] 二叉树最多节点
572. Subtree of Another Tree [Easy] 判断子树
606. Construct String from Binary Tree [Easy] 循环
623. Add One Row to Tree [Medium] BFS
653. Two Sum IV - Input is a BST [Easy] 树中两个数的和
Medium
124. Binary Tree Maximum Path Sum [Hard] 数的最大和
199. Binary Tree Right Side View [Medium] 树 BFS
222. Count Complete Tree Nodes [Medium] 二分查找
515. Find Largest Value in Each Tree Row [Medium] BFS
Hard
五、链表
Easy
21. Merge Two Sorted Lists [Easy] 链表
141-142. Linked List Cycle I & II [Easy & Medium] 链表
Medium
138. Copy List with Random Pointer [Medium] 链表
*143. Reorder List [Medium] 链表
148. Sort List [Medium] 归并排序
328. Odd Even Linked List [Medium] 135246
1143. Longest Common Subsequence [Medium] 最长公共子序列 DP
Hard
六、动态规划
Easy
Medium
62-63. Unique Paths I & II & III [Medium & Hard] 动态规划 & DFS
139-140 Word Break I & II [Medium & Hard] 动态规划 & 回溯
343. Integer Break [Medium] DP or 贪心
Hard
72. Edit Distance [Hard] 编辑距离DP
135. Candy [Hard] DP
152. Maximum Product Subarray [Medium] 子数组最大积/DP
七、回溯
Easy
Medium
Hard
八、BFS
Easy
Medium
133. Clone Graph [Medium] 复制图
***310. Minimum Height Trees [Medium] BFS
207-210. Course Schedule [I & II] [Medium] 拓扑排序/课程顺序
515. Find Largest Value in Each Tree Row [Medium] BFS
863. All Nodes Distance K in Binary Tree [Medium] 树和BFS
Hard
九、DFS
Easy
Medium
Hard
十、贪心
Easy
Medium
Hard
十一、栈和队列
Easy
Medium
394. Decode String [Medium] 栈
921. Minimum Add to Make Parentheses Valid [Medium] 栈
