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> #…

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…

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…

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…

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…

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: 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…

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…

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…

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,…

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…

Silver Cow Party Time Limit: 2000MS   Memory Limit: 65536K Total Submissions: 12674   Accepted: 5651 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…

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: 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 …

原题链接:http://poj.org/problem?id=3268 Silver Cow Party Time Limit: 2000MS   Memory Limit: 65536K Total Submissions: 15545   Accepted: 7053 Description One cow from each of N farms (1 ≤ N ≤ 1000) conveniently numbered 1..N is going to attend the big cow…

题目描述 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…

P1821 [USACO07FEB]银牛派对Silver Cow Party 题目描述 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 co…

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: 19325   Accepted: 8825 Description One cow from each of N farms (1 ≤ N ≤…

题目描述 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…

POJ 3268 Silver Cow Party (最短路径) 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 c…

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…

Silver Cow Party Time Limit : 4000/2000ms (Java/Other)   Memory Limit : 131072/65536K (Java/Other) Total Submission(s) : 1   Accepted Submission(s) : 1 Problem Description One cow from each of N farms (1 ≤ N ≤ 1000) conveniently numbered 1..N is goin…

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: 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 迪杰斯特拉+反向 题意 有n个农场,编号1到n,每个农场都有一头牛.他们想要举行一个party,其他牛到要一个定好的农场中去.每个农场之间有路相连,但是这个路是单向的,并且去了还得回来,求花费时间最多是多少? 解题思路 很容易想明白需要分两步 第一步:算出目的点到其他点的最短距离, 这一步很好实现,直接使用Dijkstra即可 第二部:算出其他点到终点的最短距离. 关键就在第二部.迪杰斯特拉算的是某一点到其他所有点的最短距离,而这次我们是求的其他点到某一点的最短…

题目传送门 1 2 题意:有向图,所有点先走到x点,在从x点返回,问其中最大的某点最短路程 分析:对图正反都跑一次最短路,开两个数组记录x到其余点的距离,这样就能求出来的最短路以及回去的最短路. POJ 3268 //#include <bits/stdc++.h> #include <cstdio> #include <queue> #include <algorithm> #include <cstring> using namespace…

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 …