摘要：
There are a total of n courses you have to take, labeled from 0 to n - 1. Some courses may have prerequisites, for example to take course 0 you have t 阅读全文
摘要：
Given a string, find the length of the longest substring without repeating characters. For example, the longest substring without repeating letters fo... 阅读全文
摘要：
You are given two linked lists representing two non-negative numbers. The digits are stored in reverse order and each of their nodes contain a single 阅读全文
摘要：
Given an array of integers, find two numbers such that they add up to a specific target number.The function twoSum should return indices of the two nu... 阅读全文
摘要：
Given a 2d grid map of'1's (land) and'0's (water), count the number of islands. An island is surrounded by water and is formed by connecting adjacent ... 阅读全文