Nicholas Y. Alford was a cat lover. He had a garden in a village and kept many cats in his garden. The cats were so cute that people in the village also loved them. One day, an evil witch visited the village. She envied the cats for being loved by ev…

题意:给出一个图,去除每条边的花费为边的长度,求用最少的花费去除部分边使得图中无圈. 思路:先将所有的边长加起来,然后减去最大生成树,即得出最小需要破坏的篱笆长度. #include <cstdio> #include <iostream> #include <algorithm> #include <cstring> #include <vector> using namespace std; int N, M; // 桩数量,篱笆数量 int…

链接:传送门 题意:有个女巫把猫全部抓走放在一个由 n 个木桩(xi,yi),m 个篱笆(起点终点木桩的编号)围成的法术领域内,我们必须用圣水才能将篱笆打开,然而圣水非常贵,所以我们尽量想降低花费来解救所有的猫 思路:这张图的生成树相当于这个领域的"框架",总的周长是一定的,只需要让"框架"最长那么其他篱笆(解救猫咪"开口"的地方)也就最短,只需要把边权处理成负数然后做最小生成树,最后 周长 + 最小生成树的路径长 即为答案 /*********…

https://vjudge.net/problem/Aizu-2224 场景嵌入得很好,如果不是再最小生成树专题里,我可能就想不到解法了. 对所有的边(栅栏)求最大生成树,剩下来的长度即解(也就是需要破环的最小边和). #include<iostream> #include<cstdio> #include<queue> #include<cstring> #include<algorithm> #include<cmath> #i…

题目链接:https://vjudge.net/problem/Aizu-2224 题目大意: 先给出 N 个点的坐标(x,y),这N个点之间有且只有M条边,接下来给出 M 条边的两端点,每条边对应的边权就是两端点的距离,断开一条边所需的花费就是这条边的边权.现在我们要断开一些边,使得剩余的边没有办法围成圈,但又要使得总花费最小.求所需的最小花费. 解题思路: 要是剩余的边没有办法围成圈,那么其实就是想要让剩余的边能够组成一棵树,所需的总花费其实就是除了这棵树以外的边的所有边权,所以我们让这颗树…

Save your cats Time limit 8000 ms Memory limit 131072 kB Problem Description Nicholas Y. Alford was a cat lover. He had a garden in a village and kept many cats in his garden. The cats were so cute that people in the village also loved them. One day,…

Save your cats 题意:存在n个点,有m条边( input中读入的是 边的端点,要先转化为边的长度 ),做一个最小生成树,使得要去除的边的长度总和最小: 思路:利用并查集和求最小生成树的方法,注意这里的排序要从大到小排,这样最后建树的消耗最大,反过来去除的最小: 当然题意不是这么直白,感觉以后看到要做一个不成环的图时,要想到最小生成树: 下面是ac代码: #include <cstdio> #include <iostream> #include <cstring…

http://acm.hust.edu.cn/vjudge/problem/viewProblem.action?id=45524 NY在自己的花园里养了很多猫.有一天,一个巫婆在N个点设置了魔法,然后有M条关系,每一条在两个点之间有栅栏. NY需要损坏这些栅栏但是需要栅栏长度这么多神奇的水,因为这种水很昂贵所以希望水用的越少越好.输出最少花费. 输入N,M表示N个点,接下来N行每行一个点的坐标,接下来M行每行两个数表示x,y之间有栅栏相连. 没有栅栏会交叉,每个圈都至少有一只猫. 题目意思就是…

Training little cats Time Limit: 2000MS   Memory Limit: 65536K Total Submissions: 9613   Accepted: 2296 Description Facer's pet cat just gave birth to a brood of little cats. Having considered the health of those lovely cats, Facer decides to make th…

Training little cats Time Limit: 2000MS   Memory Limit: 65536K Total Submissions: 9299   Accepted: 2230 Description Facer's pet cat just gave birth to a brood of little cats. Having considered the health of those lovely cats, Facer decides to make th…