Description One cow from each of N farms (1 ≤ N ≤ 1000) conveniently numbered 1..N is going to attend the big cow party to be held at farm #X (1 ≤ X ≤ N). A total of M (1 ≤ M ≤ 100,000) unidirectional (one-way roads connects pairs of farms; road i re…

Silver Cow Party Time Limit: 2000MS   Memory Limit: 65536K Total Submissions: 15156   Accepted: 6843 Description One cow from each of N farms (1 ≤ N ≤ 1000) conveniently numbered 1..N is going to attend the big cow party to be held at farm #X (1 ≤ X…

One cow from each of N farms (1 ≤ N ≤ 1000) conveniently numbered 1..N is going to attend the big cow party to be held at farm #X (1 ≤ X ≤ N). A total of M (1 ≤ M≤ 100,000) unidirectional (one-way roads connects pairs of farms; road i requires Ti (1…

非常感谢kuangbin专题啊,这道题一开始模拟邻接表做的,反向边不好处理,邻接矩阵的话舒服多了. 题意:给n头牛和m条有向边,每头牛1~n编号,求所有牛中到x编号去的最短路+回来的最短路的最大值. #include <iostream> #include <cstring> #include <cstdio> #include <algorithm> #include <queue> using namespace std; ; ; const…

题目链接:http://poj.org/problem?id=3268 Silver Cow Party Time Limit: 2000MS   Memory Limit: 65536K Total Submissions: 24527   Accepted: 11164 Description One cow from each of N farms (1 ≤ N ≤ 1000) conveniently numbered 1..N is going to attend the big co…

Silver Cow Party Descriptions 给出n个点和m条边,接着是m条边,代表从牛a到牛b需要花费c时间,现在所有牛要到牛x那里去参加聚会,并且所有牛参加聚会后还要回来,给你牛x,除了牛x之外的牛,他们都有一个参加聚会并且回来的最短时间,从这些最短时间里找出一个最大值输出 Input 第1行:三个空格分隔的整数,分别为: N, M和 X 行2 .. M +1:行 i +1描述具有三个空格分隔整数的道路 i: A i, B i和 T i.所描述的道路从农场A i运行 到农场 B…

Silver Cow Party 题目链接: http://acm.hust.edu.cn/vjudge/contest/122685#problem/D Description One cow from each of N farms (1 ≤ N ≤ 1000) conveniently numbered 1..N is going to attend the big cow party to be held at farm #X (1 ≤ X ≤ N). A total of M (1 ≤…

Silver Cow Party Time Limit:2000MS     Memory Limit:65536KB     64bit IO Format:%I64d & %I64u Submit Status Practice POJ 3268 Description One cow from each of N farms (1 ≤ N ≤ 1000) conveniently numbered 1..N is going to attend the big cow party to b…

一.题面 POJ3268 二.分析 该题的意思就是给定了一个由每个节点代表农场的有向图,选定一个农场X办party,其余农场的都要去,每个农场的cow都走最短路,走的时间最久的cow耗时多少. 了解题意后,最开始想的是直接用floyd,但是复杂度已经到10的9次方了.这题比较特殊的一点就是无论是回来还是去都与X这个点有关,所以,当我们思考去求X到其他点的最短路径时,即根据输入的图求,其实就是在求返回的时长.如果我们把输入的图的路径的方向都反一下,即$a-b$变成$b-a$,这样相当于就是求其他所…

Silver Cow Party Time Limit: 2000MS   Memory Limit: 65536K Total Submissions: 22864   Accepted: 10449 Description One cow from each of N farms (1 ≤ N ≤ 1000) conveniently numbered 1..N is going to attend the big cow party to be held at farm #X (1 ≤ X…

Silver Cow Party Time Limit:2000MS     Memory Limit:65536KB     64bit IO Format:%I64d & %I64u Submit Status Practice POJ 3268 Description One cow from each of N farms (1 ≤ N ≤ 1000) conveniently numbered 1..N is going to attend the big cow party to b…

Silver Cow Party Time Limit: 2000MS   Memory Limit: 65536K Total Submissions: 13982   Accepted: 6307 Description One cow from each of N farms (1 ≤ N ≤ 1000) conveniently numbered 1..N is going to attend the big cow party to be held at farm #X (1 ≤ X …

Silver Cow Party Time Limit: 2000MS   Memory Limit: 65536K Total Submissions: 17017   Accepted: 7767 Description One cow from each of N farms (1 ≤ N ≤ 1000) conveniently numbered 1..N is going to attend the big cow party to be held at farm #X (1 ≤ X …

Silver Cow Party Time Limit:2000MS     Memory Limit:65536KB     64bit IO Format:%I64d & %I64u Description One cow from each of N farms (1 ≤ N ≤ 1000) conveniently numbered 1..N is going to attend the big cow party to be held at farm #X (1 ≤ X ≤ N). A…

https://vjudge.net/problem/POJ-3268 一开始floyd超时了.. 对正图定点求最短,对逆图定点求最短,得到任意点到定点的往返最短路. #include<iostream> #include<cstdio> #include<queue> #include<cstring> #include<algorithm> #include<cmath> #include<stack> #define…

题目链接 http://poj.org/problem?id=3268 题意 有向图中有n个结点,编号1~n,输入终点编号x,求其他结点到x结点来回最短路长度的最大值. 思路 最短路问题,有1000个结点,Floyd算法应该会超时,我刚开始使用的Dijkstra算法也超时,原因是因为我使用一个循环遍历结点1~n,每次遍历我都使用两次Dijkstra求i到x和x到i的最短路,时间复杂度太高.降低时间复杂度的方法是先在原矩阵的基础上使用dijkstra求结点x到其余各点的最短路径,然后将矩阵转置,在…

题目链接: https://vjudge.net/problem/POJ-3268 题目大意: 有编号为1-N的牛,它们之间存在一些单向的路径.给定一头牛的编号X,其他牛要去拜访它并且拜访完之后要返回自己原来的位置,求所有牛从开始到回家的时间是多少? 思路: 所有牛都回到了家所花费的时间就是这些牛中花费时间的最大者,可以正向的Dijkstra求出从X到每个点的最短时间,然后一个骚操作:将所有边反向(swap(Map[i][j], Map[j][i])),再从x用dijkstra求出X到每个点的最…

题意:有n个地点,有m条路,问从所有点走到指定点x再走回去的最短路中的最长路径 思路:用Floyd超时的,这里用的Dijkstra. Dijkstra感觉和Prim和Kruskal的思路很像啊.我们把所有点分为两个集合:S(和源点在同一集合),T(其余点),用dis数组表示每个点到S的最短距离,vis数组记录这个点是否在S中.我们每次找出在T的一个和S距离最短的点,加到S中,这个距离就是他到源点的最短路径(听说能证,我不会证...),然后更新其他点,直到所有点都在S. 这道题从x走回去很简单,就…

其实还是从一个x点出发到所有点的最短路问题.来和回只需分别处理一下逆图和原图,两次SPFA就行了. #include<iostream> #include<cstdio> #include<cstdlib> #include<cstring> #include<string> #include<cmath> #include<map> #include<set> #include<vector> #…

题目描述 原题来自:USACO 2007 Feb. Silver N(1≤N≤1000)N (1 \le N \le 1000)N(1≤N≤1000) 头牛要去参加一场在编号为 x(1≤x≤N)x(1 \le x \le N)x(1≤x≤N) 的牛的农场举行的派对.有 M(1≤M≤100000)M(1\le M \le 100000)M(1≤M≤100000) 条有向道路,每条路长 Ti(1≤Ti≤100)T_i(1 \le T_i \le 100)T​i​​(1≤T​i​​≤100):每头牛都…

One cow from each of N farms (1 ≤ N ≤ 1000) conveniently numbered 1..N is going to attend the big cow party to be held at farm #X (1 ≤ X ≤ N). A total of M (1 ≤ M ≤ 100,000) unidirectional (one-way roads connects pairs of farms; road i requires Ti (1…

题目 Dijkstra,正反两次最短路,求两次和最大的. #define _CRT_SECURE_NO_WARNINGS //这是找出最短路加最短路中最长的来回程 //也就是正反两次最短路相加找最大的和 #include<string.h> #include<stdio.h> #include<math.h> #include<algorithm> using namespace std; ; #define typec int const typec IN…

http://poj.org/problem?id=3268 题目大意:求到x距离与从x返回和的最大值 从x点到各个点最短路好求,直接用Dijkstar,但从各个点到x点却不好求,只要把路向翻转过来也变成求从x点到各个点,直接用Dijstar dist[]记录x点到各个点的最短路径距离 #include<stdio.h> #include<stdlib.h> #include<math.h> #include<string.h> #define max(a,…

题意:由n个牧场,编号1到n.每个牧场有一头牛.现在在牧场x举办party,每头牛都去参加,然后再回到自己的牧场.牧场之间会有一些单向的路.每头牛都会让自己往返的路程最短.问所有牛当中最长的往返路程是多少. 思路:n最多到1000,floyd肯定超时.可以这样做,把图中所有的边先存起来,然后第一次用dijkstra求出以x为源点到每个点的最短距离.该最短距离为每头牛回家时的最短距离.然后建个新的图,将之前存的边反向加入图中.如之前有条从5到8距离为2的路,则此时向图中添加的边为从8到5距离为2的…

POJ 3268 Silver Cow Party Description One cow from each of N farms (1 ≤ N ≤ 1000) conveniently numbered 1..N is going to attend the big cow party to be held at farm #X (1 ≤ X ≤ N). A total of M (1 ≤ M ≤ 100,000) unidirectional (one-way roads connects…

题目链接: https://vjudge.net/problem/POJ-3268 One cow from each of N farms (1 ≤ N ≤ 1000) conveniently numbered 1..N is going to attend the big cow party to be held at farm #X (1 ≤ X ≤ N). A total of M (1 ≤ M ≤ 100,000) unidirectional (one-way roads conn…

题目链接:http://poj.org/problem?id=3268 Silver Cow Party Time Limit: 2000MS   Memory Limit: 65536K Total Submissions: 19211   Accepted: 8765 Description One cow from each of N farms (1 ≤ N ≤ 1000) conveniently numbered 1..N is going to attend the big cow…

Silver Cow Party Time Limit: 2000MS   Memory Limit: 65536K Total Submissions:28457   Accepted: 12928 Description One cow from each of N farms (1 ≤ N ≤ 1000) conveniently numbered 1..N is going to attend the big cow party to be held at farm #X (1 ≤ X …

Silver Cow Party Time Limit: 2000MS   Memory Limit: 65536K Total Submissions: 13611   Accepted: 6138 Description One cow from each of N farms (1 ≤ N ≤ 1000) conveniently numbered 1..N is going to attend the big cow party to be held at farm #X (1 ≤ X…

Silver Cow Party One cow from each of N farms (1 ≤ N ≤ 1000) conveniently numbered 1..N is going to attend the big cow party to be held at farm #X (1 ≤ X ≤ N). A total of M (1 ≤ M ≤ 100,000) unidirectional (one-way roads connects pairs of farms; road…