算法 题目 出现次数 链接 103. 二叉树的锯齿形层次遍历 2 https://leetcode-cn.com/problems/binary-tree-zigzag-level-order-traversal 72. 编辑距离 2 https://leetcode-cn.com/problems/edit-distance 46. 全排列 2 https://leetcode-cn.com/problems/permutations 23. 合并K个排序链表 2 https://leetcode-cn.com/problems/merge-k-sorted-lists 206. 反转链表 2 https://leetcode-cn.com/problems/reverse-linked-list 144. 二叉树的前序遍历 1 https://leetcode-cn.com/problems/binary-tree-preorder-traversal 15. 三数之和 1 https://leetcode-cn.com/problems/3sum 补充题8. 计算数组的小和 1 https://mp.weixin.qq.com/s/0ih4W6nawzFUPSj3GOnYTQ 300. 最长上升子序列 1 https://leetcode-cn.com/problems/longest-increasing-subsequence 199. 二叉树的右视图 1 https://leetcode-cn.com/problems/binary-tree-right-side-view 202. 快乐数 1 https://leetcode-cn.com/problems/happy-number 268. 缺失数字 1 https://leetcode-cn.com/problems/missing-number 121. 买卖股票的最佳时机 1 https://leetcode-cn.com/problems/best-time-to-buy-and-sell-stock 补充题4. 手撕快速排序 1 102. 二叉树的层序遍历 1 https://leetcode-cn.com/problems/binary-tree-level-order-traversal 236. 二叉树的最近公共祖先 1 https://leetcode-cn.com/problems/lowest-common-ancestor-of-a-binary-tree 322. 零钱兑换 1 https://leetcode-cn.com/problems/coin-change 226. 翻转二叉树 1 https://leetcode-cn.com/problems/invert-binary-tree