P3043 [USACO12JAN]牛联盟Bovine Alliance 题目描述 Bessie and her bovine pals from nearby farms have finally decided that they are going to start connecting their farms together by trails in an effort to form an alliance against the farmers. The cows in each…

P3043 [USACO12JAN]牛联盟Bovine Alliance 题目描述 Bessie and her bovine pals from nearby farms have finally decided that they are going to start connecting their farms together by trails in an effort to form an alliance against the farmers. The cows in each…

题目描述 给出n个点m条边的图,现把点和边分组,每条边只能和相邻两点之一分在一组,点可以单独一组,问分组方案数. (友情提示:每个点只能分到一条边,中文翻译有问题,英文原版有这样一句:The cows in each of the N  farms were initially instructed to build a trail to exactly one other farm) 思路 这题只要多画一画图,找一找性质就可以了. 我们先从一条链考虑: 可以看出,答案显然是四种,即四个点分别是…

传送门:https://www.luogu.org/problemnew/show/P3043 其实这道题十分简单..看到大佬们在用tarjan缩点,并查集合并.... 蒟蒻渣渣禹都不会. 渣渣禹发现,给出的图经过处理之后会出现: 环. 不是环. 不是环的情况我们有n中匹配方式(n为其点的个数) 是环的情况我们只有两种匹配方式,顺时针匹配和逆时针匹配. 所以我们dfs处理出图中有多少个环,和不是环的个数. ans 初始为1. 遇到环ans乘二,否则ans乘n(n为这个不是环的点的个数). 结束咯…

(m<n<=1e5,有重边) 题目表述有问题..... 给定一张图(不一定联通),每条边可以选择连接的两个点之一,剩余的点可以自己成对,问方案数. 一开始是真的被吓到了....觉得可写性极低的一题..... 但是两个结论如果推出来的话就蛮好的了 solution: 一开始想:对于每个块进行大小统计,然后组合数乘在一起.但是,有点麻烦: 有环的情况:对于一个联通块有环,那么就会有n个点,n条边,那就意味着会有一个联通块只有一个单独的点.单独考虑环块(下统称环块) 看看这个三元环(误),先确定第一…

P2950 [USACO09OPEN]牛绣Bovine Embroidery 题目描述 Bessie has taken up the detailed art of bovine embroidery. Cows embroider a cloth mounted in a circular hoop of integer radius d (1 <= d <= 50,000). They sew N (2 <= N <= 50,000) threads, each in a s…

[Usaco2012Jan]Bovine Alliance Time Limit: 2 Sec Memory Limit: 128 MB Description Bessie and her bovine pals from nearby farms have finally decided that they are going to start connecting their farms together by trails in an effort to form an alliance…

传送门1:http://www.usaco.org/index.php?page=viewproblem2&cpid=111 传送门2:http://www.lydsy.com/JudgeOnline/problem.php?id=2582 这道题蛮有意思的,首先对于不同的联通块,显然我们可以分别求出方案数,然后乘法原理得出最终结果. 对于每个联通块,只有三种情况: 1,有n个顶点,n - 1条边,那么这是一棵树,可以分别把每个顶点作为根,由儿子指向父亲,所以有n种方案 2,有n个顶点,n条边,…

字节码联盟 (Bytecode Alliance)宣布已正式成为 501(c)(3) 非营利组织,参与组建的企业/组织包括 Fastly.英特尔.Mozilla 和微软,此外还邀请到了 Arm.DFINITY Foundation.Embark Studios.谷歌.Shopify 和加州大学圣地亚哥分校加入并成为正式会员. Bytecode Alliance 最早成立于2019年,当时只是一个由多家企业联合发起的非正式行业组织,旨在通过协作实施标准和提出新标准,以完善 WebAssembly…

bzoj上的usaco题目还是很好的(我被虐的很惨. 有必要总结整理一下. 1592: [Usaco2008 Feb]Making the Grade 路面修整 一开始没有想到离散化.然后离散化之后就很好做了.F[I,j]表示第i个点,高度>=j或<=j,f[I,j]=min(f[i-1,j]+abs(b[j]-a[i]),f[I,j-1]) 1593: [Usaco2008 Feb]Hotel 旅馆 线段树 ★1594: [Usaco2008 Jan]猜数游戏 二分答案然后写线段树维护 15…