测试 题目 出现次数 链接 3. 无重复字符的最长子串 3 https://leetcode-cn.com/problems/longest-substring-without-repeating-characters 142. 环形链表 II 2 https://leetcode-cn.com/problems/linked-list-cycle-ii 20. 有效的括号 2 https://leetcode-cn.com/problems/valid-parentheses 53. 最大子序和 1 https://leetcode-cn.com/problems/maximum-subarray 232. 用栈实现队列 1 https://leetcode-cn.com/problems/implement-queue-using-stacks 15. 三数之和 1 https://leetcode-cn.com/problems/3sum 补充题6. 手撕堆排序 1 509. 斐波那契数 1 https://leetcode-cn.com/problems/fibonacci-number 206. 反转链表 1 https://leetcode-cn.com/problems/reverse-linked-list 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 143. 重排链表 1 https://leetcode-cn.com/problems/reorder-list 349. 两个数组的交集 1 https://leetcode-cn.com/problems/intersection-of-two-arrays 剑指 Offer 42. 连续子数组的最大和 1 https://leetcode-cn.com/problems/lian-xu-zi-shu-zu-de-zui-da-he-lcof 121. 买卖股票的最佳时机 1 https://leetcode-cn.com/problems/best-time-to-buy-and-sell-stock 5. 最长回文子串 1 https://leetcode-cn.com/problems/longest-palindromic-substring 39. 组合总和 1 https://leetcode-cn.com/problems/combination-sum 647. 回文子串 1 https://leetcode-cn.com/problems/palindromic-substrings 344. 反转字符串 1 https://leetcode-cn.com/problems/reverse-string