# Problem Description

Say you have an array for which the ith element is the price of a given stock on day i.

If you were only permitted to complete at most one transaction (ie, buy one and sell one share of the stock), design an algorithm to find the maximum profit.

# Problem Description

After robbing those houses on that street, the thief has found himself a new place for his thievery so that he will not get too much attention. This time, all houses at this place are arranged in a circle. That means the first house is the neighbor of the last one. Meanwhile, the security system for these houses remain the same as for those in the previous street.

Given a list of non-negative integers representing the amount of money of each house, determine the maximum amount of money you can rob tonight without alerting the police.

# 原因

git 默认忽略文件名大小写，所以即使文件夹大小写变更，git 也检测不到。

# Problem Description

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 you from robbing each of them is that adjacent houses have security system connected and it will automatically contact the police if two adjacent houses were broken into on the same night.

Given a list of non-negative integers representing the amount of money of each house, determine the maximum amount of money you can rob tonight without alerting the police.

# Problem Description

You are climbing a stair case. It takes n steps to reach to the top.

Each time you can either climb 1 or 2 steps. In how many distinct ways can you climb to the top?

## Problem Description

Given a non-negative integer num, repeatedly add all its digits until the result has only one digit.

For example:

Given num = 38, the process is like: 3 + 8 = 11, 1 + 1 = 2. Since 2 has only one digit, return it.

# 前言

so，我写了个nodejs程序批量的下载，不到1分钟，42个list的录音就都进入了我的硬盘。 ; ）

# connect简介

Connect is a middleware framework for node.

Connect 是 nodejs 的中间件框架。何为中间件？中间件就是用户请求和返回结果之间的一个又一个筛选工具。正如 @Luics 所说“如果把一个http处理过程比作是污水处理，中间件就像是一层层的过滤网。”