D. Selection Time Limit: 1 Sec Memory Limit: 256 MB 题目连接 http://codeforces.com/gym/100114 Description When selecting files in an application dialog, Vasya noted that he can get the same selection in different ways. A simple mouse click selects a sing…

Description 问选择一个序列上的所有数的最少操作次数,跟电脑上选择文件一样,输出操作方案. Sol 贪心. 用Shift一段文件只能使用一次,之后必须一直按Ctrl了. 然后就是看用Shift选哪段区间了. 如果选 \((l,r)\) 那么答案就是 \((C_{l-1})+(C_{n}-C_{r})+(r-l+1-C_{r}+C_{l-1})+2\) . 化简就是 \(C_{n}+r-2C_{r}-(l-1)+2C_{l-1}+2\) 这个决策点是唯一的,只需要计算答案的时候顺便统计一…

题目链接: http://codeforces.com/gym/100114 Description The computer network of “Plunder & Flee Inc.” consists of n servers and m two-way communication links. Two servers can communicate either through a direct link, or through a chain of links, by relayi…

J. Computer Network Time Limit: 1 Sec Memory Limit: 256 MB 题目连接 http://codeforces.com/gym/100114 Description The computer network of “Plunder & Flee Inc.” consists of n servers and m two-way communication links. Two servers can communicate either thr…

H. Milestones Time Limit: 1 Sec Memory Limit: 256 MB 题目连接 http://codeforces.com/gym/100114 Description The longest road of the Fairy Kingdom has n milestones. A long-established tradition defines a specific color for milestones in each region, with a…

C. Sequence Time Limit: 1 Sec Memory Limit: 256 MB 题目连接 http://codeforces.com/gym/100114 Description Integer sequences are very interesting mathematical objects. Let us examine a sequence generated with the use of two operations: doubling and “digit…

B. Island Time Limit: 1 Sec Memory Limit: 256 MB 题目连接 http://codeforces.com/gym/100114 Description On February 30th this year astronauts from the International Space Station flew over the Pacific Ocean and took a picture, on which was discovered a pr…

A. Hanoi tower Time Limit: 1 Sec Memory Limit: 256 MB 题目连接 http://codeforces.com/gym/100114 Description you the conditions of this task. There are 3 pivots: A, B, C. Initially, n disks of different diameter are placed on the pivot A: the smallest dis…

Description 给出一个图,求添加一条边使得添加后的图的桥(割边)最少. Sol Tarjan. 一遍Tarjan求割边. 我们发现连接的两个点一定是这两个点之间的路径上的桥最多,然后就可以贪心的搞. Tarjan的同时记录一下到该点的桥个数的最大值和次大值,然后统计答案就可以. 注意要满足这两个点不能再DFS路径上有公共边,意思就是说在每次回溯的时候统计一下最大值和次大值. Code #include<cstdio> #include<vector> #include&l…

一句话题意:x0=1,xi+1=(Axi+xi%B)%C,如果x序列中存在最早的两个相同的元素,输出第二次出现的位置,若在2e7内无解则输出-1. 题解:都不到100天就AFO了才来学这floyd判圈算法. 介绍一下floyd判圈算法:该算法适用于在线性时间复杂度内判断有限自动机.迭代函数.链表中是否有环,求环的起点(即链长)和环长. 可以先这么做:首先从起点S出发,给定两个指针,一个快指针一个慢指针,然后每次快指针走1步,慢指针走2步,直到相遇为止.如果已经到达终点/达到规定步数时仍然没有相遇…