交叉排序

144. Binary Tree Preorder Traversal

74. 第一个错误的代码版本

62. 搜索旋转排序数组

61. 搜索区间

159. 寻找旋转排序数组中的最小值

75. 寻找峰值

447. 在大数组中查找

28. 搜索二维矩阵

127. Word Ladder

14.二分查找

35. Search Insert Position

7. Reverse Integer

3. Longest Substring Without Repeating Characters

145. Binary Tree Postorder Traversal

Binary Tree Inorder Traversal

LRU Cache

47. Permutations II

46. Permutations

18. 带重复元素的子集

9. Palindrome Number

子集 subsets

28. Implement strStr()

326. Power of Three

342. Power of Four

155. Minimum Depth of Binary Tree

97. Maximum Depth of Binary Tree

Binary Tree Postorder Traversal

Binary Tree Preorder Traversal

121. Best Time to Buy and Sell Stock

2. Add Two Numbers

Given a linked list, swap every two adjacent nodes and return its head.For example, Given 1->2->3->4, you should return the list as 2->1->4->3.Your algorithm should use only constant space. You may no

235. Lowest Common Ancestor of a Binary Search Tree

326. Power of Three

169. Majority Element

217. Contains Duplicate

171. Excel Sheet Column Number

Given two strings s and t, write a function to determine if t is an anagram of s. For example, s = “anagram”, t = “nagaram”, return true. s = “rat”, t = “car”, return false.Note: You may assume

202. Happy Number

70. Climbing Stairs