P2883 [USACO07MAR]牛交通Cow Traffic 对于每一条边$(u,v)$ 设入度为0的点到$u$有$f[u]$种走法 点$n$到$v$(通过反向边)有$f2[v]$种走法 显然经过这条边的方案数为$f[u]*f2[v]$ 两边递推处理$f$数组,然后枚举每条边取个$max$. #include<iostream> #include<cstdio> #include<cstring> #include<queue> using namesp…

P2883 [USACO07MAR]牛交通Cow Traffic 随着牛的数量增加,农场的道路的拥挤现象十分严重,特别是在每天晚上的挤奶时间.为了解决这个问题,FJ决定研究这个问题,以能找到导致拥堵现象的瓶颈所在. 牧场共有M条单向道路,每条道路连接着两个不同的交叉路口,为了方便研究,FJ将这些交叉路口编号为1..N,而牛圈位于交叉路口N.任意一条单向道路的方向一定是是从编号低的路口到编号高的路口,因此农场中不会有环型路径.同时,可能存在某两个交叉路口不止一条单向道路径连接的情况. 在挤奶时间到…

P3045 [USACO12FEB]牛券Cow Coupons 71通过 248提交 题目提供者洛谷OnlineJudge 标签USACO2012云端 难度提高+/省选- 时空限制1s / 128MB 提交  讨论  题解 最新讨论更多讨论 86分求救 题目描述 Farmer John needs new cows! There are N cows for sale (1 <= N <= 50,000), and FJ has to spend no more than his budget…

题目背景 [Usaco2008 Jan] 题目描述 N (1 ≤ N ≤ 100) cows, conveniently numbered 1..N, are participating in a programming contest. As we all know, some cows code better than others. Each cow has a certain constant skill rating that is unique among the competito…

P2952 [USACO09OPEN]牛线Cow Line 题目描述 Farmer John's N cows (conveniently numbered 1..N) are forming a line. The line begins with no cows and then, as time progresses, one by one, the cows join the line on the left or right side. Every once in a while, s…

P3014 [USACO11FEB]牛线Cow Line 题目背景 征求翻译.如果你能提供翻译或者题意简述,请直接发讨论,感谢你的贡献. 题目描述 The N (1 <= N <= 20) cows conveniently numbered 1...N are playing yet another one of their crazy games with Farmer John. The cows will arrange themselves in a line and ask Far…

P3111 [USACO14DEC]牛慢跑Cow Jog_Sliver 题目描述 The cows are out exercising their hooves again! There are N cows jogging on an infinitely-long single-lane track (1 <= N <= 100,000). Each cow starts at a distinct position on the track, and some cows jog at…

如果在阅读本文之前对于康托展开没有了解的同学请戳一下这里:  简陋的博客    百度百科 题目描述 N(1<=N<=20)头牛,编号为1...N,正在与FJ玩一个疯狂的游戏.奶牛会排成一行(牛线),问FJ此时的行号是多少.之后,FJ会给牛一个行号,牛必须按照新行号排列成线. 行号是通过以字典序对行的所有排列进行编号来分配的.比如说:FJ有5头牛,让他们排为行号3,排列顺序为: 1:1 2 3 4 5 2:1 2 3 5 4 3:1 2 4 3 5 因此,牛将在牛线1 2 4 3 5中. 之后,…

传送门 题目大意:n头牛在单行道n个位置,开始用不同的速度跑步. 当后面的牛追上前面的牛,后面的牛会和前面的牛以一样的速度 跑,称为一个小团体.问:ts后有多少个小团体. 题解:模拟 倒着扫一遍,因为某头牛后面的牛对这头牛的速度没影响. 计算出ts后牛的终点,如果能撞上前面最慢的牛,那么小团体数+1 注意开long long 一开始不理解为什么倒着扫, 因为如果正着扫,看第i头牛能否撞上i+1头, 我们不确定第i+1头牛的速度,可能第i+1头牛 速度很快,追上i+2头牛速度减缓,从而被第i头牛追…

https://www.luogu.org/problem/show?pid=2419 题目背景 [Usaco2008 Jan] 题目描述 N (1 ≤ N ≤ 100) cows, conveniently numbered 1..N, are participating in a programming contest. As we all know, some cows code better than others. Each cow has a certain constant ski…