摘要：
Given a string, find the length of the longest substring without repeating characters. Examples: 解法: 建立一个大小为256整形数组，用来记录每个字符上一次出现的位置。longest记录最长的子串长度， 阅读全文
摘要：
You are given two non-empty linked lists representing two non-negative integers. The digits are stored in reverse order and each of their nodes contai 阅读全文
摘要：
Given an array of integers, return indices of the two numbers such that they add up to a specific target. You may assume that each input would have ex 阅读全文