我最近开发的CodeTop网站可以按照部门、难度筛选，比markdown更方便检索 题目 出现次数 链接 232. 用栈实现队列 10 https://leetcode-cn.com/problems/implement-queue-using-stacks 160. 相交链表 8 https://leetcode-cn.com/problems/intersection-of-two-linked-lists 1. 两数之和 7 https://leetcode-cn.com/problems/two-sum 21. 合并两个有序链表 7 https://leetcode-cn.com/problems/merge-two-sorted-lists 179. 最大数 5 https://leetcode-cn.com/problems/largest-number 704. 二分查找 5 https://leetcode-cn.com/problems/binary-search 146. LRU缓存机制 5 https://leetcode-cn.com/problems/lru-cache 226. 翻转二叉树 4 https://leetcode-cn.com/problems/invert-binary-tree 206. 反转链表 4 https://leetcode-cn.com/problems/reverse-linked-list 2. 两数相加 4 https://leetcode-cn.com/problems/add-two-numbers 82. 删除排序链表中的重复元素 II 4 https://leetcode-cn.com/problems/remove-duplicates-from-sorted-list-ii 72. 编辑距离 3 https://leetcode-cn.com/problems/edit-distance 15. 三数之和 3 https://leetcode-cn.com/problems/3sum 94. 二叉树的中序遍历 3 https://leetcode-cn.com/problems/binary-tree-inorder-traversal 34. 在排序数组中查找元素的第一个和最后一个位置 3 https://leetcode-cn.com/problems/find-first-and-last-position-of-element-in-sorted-array 102. 二叉树的层序遍历 3 https://leetcode-cn.com/problems/binary-tree-level-order-traversal 3. 无重复字符的最长子串 3 https://leetcode-cn.com/problems/longest-substring-without-repeating-characters 117. 填充每个节点的下一个右侧节点指针 II 3 https://leetcode-cn.com/problems/populating-next-right-pointers-in-each-node-ii 76. 最小覆盖子串 3 https://leetcode-cn.com/problems/minimum-window-substring 445. 两数相加 II 3 https://leetcode-cn.com/problems/add-two-numbers-ii 19. 删除链表的倒数第N个节点 2 https://leetcode-cn.com/problems/remove-nth-node-from-end-of-list 补充题5. 手撕归并排序 2 https://leetcode-cn.com/problems/sort-an-array 105. 从前序与中序遍历序列构造二叉树 2 https://leetcode-cn.com/problems/construct-binary-tree-from-preorder-and-inorder-traversal 199. 二叉树的右视图 2 https://leetcode-cn.com/problems/binary-tree-right-side-view 141. 环形链表 2 https://leetcode-cn.com/problems/linked-list-cycle 136. 只出现一次的数字 2 https://leetcode-cn.com/problems/single-number 剑指 Offer 51. 数组中的逆序对 2 https://leetcode-cn.com/problems/shu-zu-zhong-de-ni-xu-dui-lcof 113. 路径总和 II 2 https://leetcode-cn.com/problems/path-sum-ii 405. 数字转换为十六进制数 2 https://leetcode-cn.com/problems/convert-a-number-to-hexadecimal 215. 数组中的第K个最大元素 2 https://leetcode-cn.com/problems/kth-largest-element-in-an-array 110. 平衡二叉树 2 https://leetcode-cn.com/problems/balanced-binary-tree 剑指 Offer 22. 链表中倒数第k个节点 2 https://leetcode-cn.com/problems/lian-biao-zhong-dao-shu-di-kge-jie-dian-lcof 239. 滑动窗口最大值 2 https://leetcode-cn.com/problems/sliding-window-maximum 145. 二叉树的后序遍历 2 https://leetcode-cn.com/problems/binary-tree-postorder-traversal 25. K 个一组翻转链表 2 https://leetcode-cn.com/problems/reverse-nodes-in-k-group 236. 二叉树的最近公共祖先 2 https://leetcode-cn.com/problems/lowest-common-ancestor-of-a-binary-tree 23. 合并K个排序链表 1 https://leetcode-cn.com/problems/merge-k-sorted-lists 53. 最大子序和 1 https://leetcode-cn.com/problems/maximum-subarray 718. 最长重复子数组 1 https://leetcode-cn.com/problems/maximum-length-of-repeated-subarray 378. 有序矩阵中第K小的元素 1 https://leetcode-cn.com/problems/kth-smallest-element-in-a-sorted-matrix 154. 寻找旋转排序数组中的最小值 II 1 https://leetcode-cn.com/problems/find-minimum-in-rotated-sorted-array-ii 295. 数据流的中位数 1 https://leetcode-cn.com/problems/find-median-from-data-stream 142. 环形链表 II 1 https://leetcode-cn.com/problems/linked-list-cycle-ii 144. 二叉树的前序遍历 1 https://leetcode-cn.com/problems/binary-tree-preorder-traversal 42. 接雨水 1 https://leetcode-cn.com/problems/trapping-rain-water 167. 两数之和 II - 输入有序数组 1 https://leetcode-cn.com/problems/two-sum-ii-input-array-is-sorted 54. 螺旋矩阵 1 https://leetcode-cn.com/problems/spiral-matrix 114. 二叉树展开为链表 1 https://leetcode-cn.com/problems/flatten-binary-tree-to-linked-list 153. 寻找旋转排序数组中的最小值 1 https://leetcode-cn.com/problems/find-minimum-in-rotated-sorted-array 剑指 Offer 10- I. 斐波那契数列 1 https://leetcode-cn.com/problems/fei-bo-na-qi-shu-lie-lcof 88. 合并两个有序数组 1 https://leetcode-cn.com/problems/merge-sorted-array 5. 最长回文子串 1 https://leetcode-cn.com/problems/longest-palindromic-substring 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 300. 最长上升子序列 1 https://leetcode-cn.com/problems/longest-increasing-subsequence 415. 字符串相加 1 https://leetcode-cn.com/problems/add-strings 138. 复制带随机指针的链表 1 https://leetcode-cn.com/problems/copy-list-with-random-pointer 剑指 Offer 62. 圆圈中最后剩下的数字 1 https://leetcode-cn.com/problems/yuan-quan-zhong-zui-hou-sheng-xia-de-shu-zi-lcof 98. 验证二叉搜索树 1 https://leetcode-cn.com/problems/validate-binary-search-tree 402. 移掉K位数字 1 https://leetcode-cn.com/problems/remove-k-digits 208. 实现 Trie (前缀树) 1 https://leetcode-cn.com/problems/implement-trie-prefix-tree 528. 按权重随机选择 1 https://leetcode-cn.com/problems/random-pick-with-weight 680. 验证回文字符串 Ⅱ 1 https://leetcode-cn.com/problems/valid-palindrome-ii 349. 两个数组的交集 1 https://leetcode-cn.com/problems/intersection-of-two-arrays 443. 压缩字符串 1 https://leetcode-cn.com/problems/string-compression 225. 用队列实现栈 1 https://leetcode-cn.com/problems/implement-stack-using-queues 83. 删除排序链表中的重复元素 1 https://leetcode-cn.com/problems/remove-duplicates-from-sorted-list 92. 反转链表 II 1 https://leetcode-cn.com/problems/reverse-linked-list-ii 97. 交错字符串 1 https://leetcode-cn.com/problems/interleaving-string 227. 基本计算器 II 1 https://leetcode-cn.com/problems/basic-calculator-ii 169. 多数元素 1 https://leetcode-cn.com/problems/majority-element 20. 有效的括号 1 https://leetcode-cn.com/problems/valid-parentheses 139. 单词拆分 1 https://leetcode-cn.com/problems/word-break 547. 省份数量（原朋友圈） 1 https://leetcode-cn.com/problems/number-of-provinces 26. 删除排序数组中的重复项 1 https://leetcode-cn.com/problems/remove-duplicates-from-sorted-array 369. 给单链表加一 1 https://leetcode-cn.com/problems/plus-one-linked-list 补充题4. 手撕快速排序 1 https://leetcode-cn.com/problems/sort-an-array 101. 对称二叉树 1 https://leetcode-cn.com/problems/symmetric-tree 62. 不同路径 1 https://leetcode-cn.com/problems/unique-paths 513. 找树左下角的值 1 https://leetcode-cn.com/problems/find-bottom-left-tree-value 79. 单词搜索 1 https://leetcode-cn.com/problems/word-search 283. 移动零 1 https://leetcode-cn.com/problems/move-zeroes 48. 旋转图像 1 https://leetcode-cn.com/problems/rotate-image 670. 最大交换 1 https://leetcode-cn.com/problems/maximum-swap 703. 数据流中的第K大元素 1 https://leetcode-cn.com/problems/kth-largest-element-in-a-stream 剑指 Offer 27. 二叉树的镜像 1 https://leetcode-cn.com/problems/er-cha-shu-de-jing-xiang-lcof 241. 为运算表达式设计优先级 1 https://leetcode-cn.com/problems/different-ways-to-add-parentheses 746. 使用最小花费爬楼梯 1 https://leetcode-cn.com/problems/min-cost-climbing-stairs 187. 重复的DNA序列 1 https://leetcode-cn.com/problems/repeated-dna-sequences 面试题 01.06. 字符串压缩 1 https://leetcode-cn.com/problems/compress-string-lcci 958. 二叉树的完全性检验 1 https://leetcode-cn.com/problems/check-completeness-of-a-binary-tree 剑指 Offer 33. 二叉搜索树的后序遍历序列 1 https://leetcode-cn.com/problems/er-cha-sou-suo-shu-de-hou-xu-bian-li-xu-lie-lcof 727. 最小窗口子序列 1 https://leetcode-cn.com/problems/minimum-window-subsequence 118. 杨辉三角 1 https://leetcode-cn.com/problems/pascals-triangle 392. 判断子序列 1 https://leetcode-cn.com/problems/is-subsequence 73. 矩阵置零 1 https://leetcode-cn.com/problems/set-matrix-zeroes 47. 全排列 II 1 https://leetcode-cn.com/problems/permutations-ii 31. 下一个排列 1 https://leetcode-cn.com/problems/next-permutation 151. 翻转字符串里的单词 1 https://leetcode-cn.com/problems/reverse-words-in-a-string 200. 岛屿数量 1 https://leetcode-cn.com/problems/number-of-islands 剑指 Offer 48. 最长不含重复字符的子字符串 1 https://leetcode-cn.com/problems/zui-chang-bu-han-zhong-fu-zi-fu-de-zi-zi-fu-chuan-lcof 1038. 从二叉搜索树到更大和树 1 https://leetcode-cn.com/problems/binary-search-tree-to-greater-sum-tree 123. 买卖股票的最佳时机 III 1 https://leetcode-cn.com/problems/best-time-to-buy-and-sell-stock-iii 257. 二叉树的所有路径 1 https://leetcode-cn.com/problems/binary-tree-paths 75. 颜色分类 1 https://leetcode-cn.com/problems/sort-colors 628. 三个数的最大乘积 1 https://leetcode-cn.com/problems/maximum-product-of-three-numbers