说明：dfs，即深度优先遍历的演示，帮助人直观的理解深度优先遍历

说明：动态规划相关的，用最开始的背包问题开始讲起，然后进行各种延申，帮助人理解动态规划

说明：浙江大学的acm模板，比较全面也比较权威，质量很好，总结了很多算法的模板

说明：算法竞赛入门必选的书籍和源码集合，值得收藏。

说明：acm比赛模板，大神制作，分享给大家

说明：You are given an integer sequence of length n, a1,…,an. Let us consider performing the following n operations on an empty sequence b. The i-th operation is as follows: Append ai to the end of b. Reverse the order of the elements in b. Find the sequence b obtained after these n operations. Constraints 1≤n≤2×105 0≤ai≤109 n and ai are integers. Input Input is given from Standard Input in the following format: n a1 a2 … an Output Print n integers in a line with spaces in between. The i-th integer should be bi. Sample Input 1 4 1 2 3 4 Sample Output 1 4 2 1 3

说明：Avin is observing the cars at a crossroads. He finds that there are n cars running in the east-west direction with the i-th car passing the intersection at time ai . There are another m cars running in the north-south direction with the i-th car passing the intersection at time bi . If two cars passing the intersections at the same time, a traffic crash occurs. In order to achieve world peace and harmony, all the cars running in the north-south direction wait the same amount of integral time so that no two cars bump. You are asked the minimum waiting time.

说明：For a positive integer n, let’s denote function f(n,m) as the m-th smallest integer x that x>n and gcd(x,n)=1. For example, f(5,1)=6 and f(5,5)=11. You are given the value of m and (f(n,m)?n)⊕n, where ``⊕’’ denotes the bitwise XOR operation. Please write a program to find the smallest positive integer n that (f(n,m)?n)⊕n=k, or determine it is impossible. Input The first line of the input contains an integer T(1≤T≤10), denoting the number of test cases. In each test case, there are two integers k,m(1≤k≤1018,1≤m≤100). Output For each test case, print a single line containing an integer, denoting the smallest n. If there is no solution, output ``-1’’ instead.

说明：模拟操作系统的窗口点击置顶问题。采用链表的存储结构实现。若点击到对应窗口则置顶，点击位置不属于任何窗口则无变化。

说明：刘汝佳的《算法入门经典》的课后答案一书，帮助学习ACM算法的同学快速掌握知识点

说明：利用树状数组求逆序对，小白萌新入门算法示例

说明：刘汝佳的经典书，算法竞赛的入门经典，适合小白使用

说明：ACM刷题网站部分题目答案，有的是自己写的，有的是百度的，都测试过了

说明：查并集系列题型ACM参考代码和部分教程,谢谢

说明：背包系列题型ACM参考代码和部分教程,谢谢

说明：博弈系列题型ACM参考代码和部分教程,谢谢

说明：差分约束系统ACM参考代码和部分教程,谢谢

说明：ACM一些整理的最近A题记录,希望能行吧

说明：ACM国际大学生程序设计竞赛 算法与实现 俞勇

说明：National Training Team 2001 Proceedings

说明：National Training Team 2000 Proceedings

说明：National Training Team 1999 Proceedings

说明：National Training Team 2008 Proceedings

说明：National Training Team 2009 Proceedings

说明：National Training Team 2013 Proceedings

说明：National Training Team 2014 Proceedings

说明：ACM/ICPC algorithm programming contest template (new)

说明：POJ3468,线段树处理，注意longlongint