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 53. 最大子序和 5 https://leetcode-cn.com/problems/maximum-subarray 206. 反转链表 3 https://leetcode-cn.com/problems/reverse-linked-list 110. 平衡二叉树 2 https://leetcode-cn.com/problems/balanced-binary-tree 144. 二叉树的前序遍历 2 https://leetcode-cn.com/problems/binary-tree-preorder-traversal 54. 螺旋矩阵 2 https://leetcode-cn.com/problems/spiral-matrix 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 215. 数组中的第K个最大元素 1 https://leetcode-cn.com/problems/kth-largest-element-in-an-array 300. 最长上升子序列 1 https://leetcode-cn.com/problems/longest-increasing-subsequence 146. LRU缓存机制 1 https://leetcode-cn.com/problems/lru-cache 88. 合并两个有序数组 1 https://leetcode-cn.com/problems/merge-sorted-array 94. 二叉树的中序遍历 1 https://leetcode-cn.com/problems/binary-tree-inorder-traversal 补充题4. 手撕快速排序 1 https://leetcode-cn.com/problems/sort-an-array 224. 基本计算器 1 https://leetcode-cn.com/problems/basic-calculator 152. 乘积最大子数组 1 https://leetcode-cn.com/problems/maximum-product-subarray 232. 用栈实现队列 1 https://leetcode-cn.com/problems/implement-queue-using-stacks 102. 二叉树的层序遍历 1 https://leetcode-cn.com/problems/binary-tree-level-order-traversal 69. x 的平方根 1 https://leetcode-cn.com/problems/sqrtx 补充题5. 手撕归并排序 1 https://leetcode-cn.com/problems/sort-an-array 41. 缺失的第一个正数 1 https://leetcode-cn.com/problems/first-missing-positive 14. 最长公共前缀 1 https://leetcode-cn.com/problems/longest-common-prefix 160. 相交链表 1 https://leetcode-cn.com/problems/intersection-of-two-linked-lists 剑指 Offer 31. 栈的压入、弹出序列 1 https://leetcode-cn.com/problems/zhan-de-ya-ru-dan-chu-xu-lie-lcof 141. 环形链表 1 https://leetcode-cn.com/problems/linked-list-cycle 226. 翻转二叉树 1 https://leetcode-cn.com/problems/invert-binary-tree 704. 二分查找 1 https://leetcode-cn.com/problems/binary-search 2. 两数相加 1 https://leetcode-cn.com/problems/add-two-numbers 剑指 Offer 54. 二叉搜索树的第k大节点 1 https://leetcode-cn.com/problems/er-cha-sou-suo-shu-de-di-kda-jie-dian-lcof 142. 环形链表 II 1 https://leetcode-cn.com/problems/linked-list-cycle-ii 3. 无重复字符的最长子串 1 https://leetcode-cn.com/problems/longest-substring-without-repeating-characters