Zhang Junda AHEADer

一行 Python 实现树

使用 Python 内置的 defaultdict，我们可以很容易的定义一个树形数据结构：

def tree(): return defaultdict(tree)

就是这样！

##分布式系统(Distributed System)资料

#####希望转载的朋友，你可以不用联系我．但是一定要保留原文链接，因为这个项目还在继续也在不定期更新．希望看到文章的朋友能够学到更多．

《Reconfigurable Distributed Storage for Dynamic Networks》

介绍:这是一篇介绍在动态网络里面实现分布式系统重构的paper.论文的作者(导师)是MIT读博的时候是做分布式系统的研究的,现在在NUS带学生,不仅仅是分布式系统,还有无线网络.如果感兴趣可以去他的主页了解.

Code is clean if it can be understood easily – by everyone on the team. Clean code can be read and enhanced by a developer other than its original author. With understandability comes readability, changeability, extensibility and maintainability.

General rules

Follow standard conventions.
Keep it simple stupid. Simpler is always better. Reduce complexity as much as possible.
Boy scout rule. Leave the campground cleaner than you found it.
Always find root cause. Always look for the root cause of a problem.

Design rules

Update 28 July 2019: An updated version of this guide for Ubuntu Server 18.04 LTS is now available. Feel free to check it out.

Update 23 May 2020: This guide is ALREADY OUTDATED and might no longer work with new versions of Ubuntu and VirtualBox. Please consider switching to the updated guide instead. I will no longer respond to the replies to this gist. Thank you.

Mounting VirtualBox shared folders on Ubuntu Server 16.04 LTS

This guide will walk you through steps on how to setup a VirtualBox shared folder inside your Ubuntu Server guest. Tested on Ubuntu Server 16.04.3 LTS (Xenial Xerus)

	/*
	* This program is free software: you can redistribute it and/or modify
	* it under the terms of the GNU General Public License as published by
	* the Free Software Foundation, either version 3 of the License, or
	* (at your option) any later version.
	*/

	#include <arpa/inet.h>
	#include <linux/if_packet.h>
	#include <stdio.h>

	#include <stdio.h>

	#define N 9
	#define UNASSIGNED 0

	int is_exist_row(int grid[N][N], int row, int num){
	for (int col = 0; col < 9; col++) {
	if (grid[row][col] == num) {
	return 1;
	}