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 adjacen 阅读全文

摘要： Given a binary tree, imagine yourself standing on the right side of it, return the values of the nodes you can see ordered from top to bottom. For exa 阅读全文

摘要： You are a professional robber planning to rob houses along a street. Each house has a certain amount of money stashed, the only constraint stopping yo 阅读全文

摘要： Write a function that takes an unsigned integer and returns the number of ’1' bits it has (also known as the Hamming weight). For example, the 32-bit 阅读全文

摘要： Reverse bits of a given 32 bits unsigned integer. For example, given input 43261596 (represented in binary as 00000010100101000001111010011100), retur 阅读全文

摘要： Rotate an array of n elements to the right by k steps. For example, with n = 7 and k = 3, the array [1,2,3,4,5,6,7] is rotated to [5,6,7,1,2,3,4]. 就是把 阅读全文

摘要： 题目比较简单，就是好好熟悉一下答题系统，练练手 阅读全文

摘要： All DNA is composed of a series of nucleotides abbreviated as A, C, G, and T, for example: "ACGAATTCCG". When studying DNA, it is sometimes useful to 阅读全文

摘要： Mac OS X - 重置 MySQL Root 密码您是否忘记了Mac OS 的MySQL的root密码? 通过以下4步就可重新设置新密码：1. 停止 mysql server. 通常是在 '系统偏好设置' > MySQL > 'Stop MySQL Server'2. 打开终端，输入： sudo 阅读全文

摘要： Given an input string, reverse the string word by word. A word is defined as a sequence of non-space characters. The input string does not contain lea 阅读全文