| 232. 用栈实现队列 | 4 | https://leetcode-cn.com/problems/implement-queue-using-stacks |
| 146. LRU缓存机制 | 3 | https://leetcode-cn.com/problems/lru-cache |
| 121. 买卖股票的最佳时机 | 3 | https://leetcode-cn.com/problems/best-time-to-buy-and-sell-stock |
| 101. 对称二叉树 | 3 | https://leetcode-cn.com/problems/symmetric-tree |
| 25. K 个一组翻转链表 | 3 | https://leetcode-cn.com/problems/reverse-nodes-in-k-group |
| 98. 验证二叉搜索树 | 2 | https://leetcode-cn.com/problems/validate-binary-search-tree |
| 103. 二叉树的锯齿形层次遍历 | 2 | https://leetcode-cn.com/problems/binary-tree-zigzag-level-order-traversal |
| 141. 环形链表 | 2 | https://leetcode-cn.com/problems/linked-list-cycle |
| 53. 最大子序和 | 2 | https://leetcode-cn.com/problems/maximum-subarray |
| 64. 最小路径和 | 2 | https://leetcode-cn.com/problems/minimum-path-sum |
| 200. 岛屿数量 | 2 | https://leetcode-cn.com/problems/number-of-islands |
| 补充题1. 排序奇升偶降链表 | 2 | https://mp.weixin.qq.com/s/0WVa2wIAeG0nYnVndZiEXQ |
| 94. 二叉树的中序遍历 | 1 | https://leetcode-cn.com/problems/binary-tree-inorder-traversal |
| 补充题6. 手撕堆排序 | 1 | https://leetcode-cn.com/problems/sort-an-array |
| 剑指 Offer 53 - I. 在排序数组中查找数字 I | 1 | https://leetcode-cn.com/problems/zai-pai-xu-shu-zu-zhong-cha-zhao-shu-zi-lcof |
| 122. 买卖股票的最佳时机 II | 1 | https://leetcode-cn.com/problems/best-time-to-buy-and-sell-stock-ii |
| 230. 二叉搜索树中第K小的元素 | 1 | https://leetcode-cn.com/problems/kth-smallest-element-in-a-bst |
| 142. 环形链表 II | 1 | https://leetcode-cn.com/problems/linked-list-cycle-ii |
| 69. x 的平方根 | 1 | https://leetcode-cn.com/problems/sqrtx |
| 611. 有效三角形的个数 | 1 | https://leetcode-cn.com/problems/valid-triangle-number |
| 221. 最大正方形 | 1 | https://leetcode-cn.com/problems/maximal-square |
| 剑指 Offer 51. 数组中的逆序对 | 1 | https://leetcode-cn.com/problems/shu-zu-zhong-de-ni-xu-dui-lcof |
| 43. 字符串相乘 | 1 | https://leetcode-cn.com/problems/multiply-strings |
| 补充题14. 阿拉伯数字转中文数字 | 1 | |
| 16. 最接近的三数之和 | 1 | https://leetcode-cn.com/problems/3sum-closest |
| 102. 二叉树的层序遍历 | 1 | https://leetcode-cn.com/problems/binary-tree-level-order-traversal |
| 215. 数组中的第K个最大元素 | 1 | https://leetcode-cn.com/problems/kth-largest-element-in-an-array |
| 1201. 丑数 III | 1 | https://leetcode-cn.com/problems/ugly-number-iii |
| 240. 搜索二维矩阵 II | 1 | https://leetcode-cn.com/problems/search-a-2d-matrix-ii |
| 剑指 Offer 41. 数据流中的中位数 | 1 | https://leetcode-cn.com/problems/shu-ju-liu-zhong-de-zhong-wei-shu-lcof |
| 112. 路径总和 | 1 | https://leetcode-cn.com/problems/path-sum |
| 3. 无重复字符的最长子串 | 1 | https://leetcode-cn.com/problems/longest-substring-without-repeating-characters |
| 剑指 Offer 59 - II. 队列的最大值 | 1 | https://leetcode-cn.com/problems/dui-lie-de-zui-da-zhi-lcof |
| 297. 二叉树的序列化与反序列化 | 1 | https://leetcode-cn.com/problems/serialize-and-deserialize-binary-tree |
| 92. 反转链表 II | 1 | https://leetcode-cn.com/problems/reverse-linked-list-ii |
| 226. 翻转二叉树 | 1 | https://leetcode-cn.com/problems/invert-binary-tree |
| 440. 字典序的第K小数字 | 1 | https://leetcode-cn.com/problems/k-th-smallest-in-lexicographical-order |
| 206. 反转链表 | 1 | https://leetcode-cn.com/problems/reverse-linked-list |
| 42. 接雨水 | 1 | https://leetcode-cn.com/problems/trapping-rain-water |
| 704. 二分查找 | 1 | https://leetcode-cn.com/problems/binary-search |
| 60. 第k个排列 | 1 | https://leetcode-cn.com/problems/permutation-sequence |
| 516. 最长回文子序列 | 1 | https://leetcode-cn.com/problems/longest-palindromic-subsequence |
| 718. 最长重复子数组 | 1 | https://leetcode-cn.com/problems/maximum-length-of-repeated-subarray |
| 5. 最长回文子串 | 1 | https://leetcode-cn.com/problems/longest-palindromic-substring |
| 155. 最小栈 | 1 | https://leetcode-cn.com/problems/min-stack |
| 33. 搜索旋转排序数组 | 1 | https://leetcode-cn.com/problems/search-in-rotated-sorted-array |
| 113. 路径总和 II | 1 | https://leetcode-cn.com/problems/path-sum-ii |
| 143. 重排链表 | 1 | https://leetcode-cn.com/problems/reorder-list |
| 148. 排序链表 | 1 | https://leetcode-cn.com/problems/sort-list |
| 138. 复制带随机指针的链表 | 1 | https://leetcode-cn.com/problems/copy-list-with-random-pointer |