题目:p条路,连接n个节点,现在需要从节点1到节点n,不重复走过一条路且走t次,最小化这t次中连接两个节点最长的那条路的值. 分析:二分答案,对于<=二分的值的边建边,跑一次最大流即可. #include <set> #include <map> #include <list> #include <cmath> #include <queue> #include <stack> #include <string> #…

题目大意: 给出一张无向图,找出T条从1..N的路径,互不重复,求走过的所有边中的最大值最小是多少. 算法讨论: 首先最大值最小就提醒我们用二分,每次二分一个最大值,然后重新构图,把那些边权符合要求的边加入新图,在新图上跑网络流. 这题有许多注意的地方: 1.因为是无向图,所以我们在加正向边和反向边的时候,流量都是1,而不是正向边是1,反向边是0. 2.题目中说这样的路径可能不止t条,所以我们在最后二分判定的时候不能写 == t,而是要 >= t. 3.这题很容易T ,表示我T了N遍,弱菜啊.…

Description Farmer John is constructing a new milking machine and wishes to keep it secret as long as possible. He has hidden in it deep within his farm and needs to be able to get to the machine without being detected. He must make a total of T (1 <…

Secret Milking Machine Time Limit: 1000MS   Memory Limit: 65536K Total Submissions: 12324   Accepted: 3589 Description Farmer John is constructing a new milking machine and wishes to keep it secret as long as possible. He has hidden in it deep within…

题目大意:N个点P条边,令存在T条从1到N的路径,求路径上的边权的最大值最小为多少 思路:做了好多二分+最大流的题了,思路很好出 二分出最大边权后建图,跑dinic 问题是....这题是卡常数的好题!!!!! T了8发以后实在受不了,瞄了眼网上的程序,齐刷刷的邻接矩阵....论邻接矩阵的优越性 但不信邪的我终于反复优化常数后邻接表A了 //TLE的程序 #include <stdio.h> #include <iostream> #include <string.h>…

[题意]n个点的一个无向图,在保证存在T条从1到n的不重复路径(任意一条边都不能重复)的前提下,要使得这t条路上经过的最长路径最短. 之所以把"经过的最长路径最短"划个重点是因为前面刚做了POJ2112那种求最长路径长度和最短的题,不要弄混了.在那道题中因为需要限制的是路径长度和,所以需要Floyd预处理路径,然后拆点变二分图防止间接流量边.然而这道题我们却不需要拆点了,直接建图即可.(类似最短路径和最小生成树的区别) [建图]建一个源点连一条T流量的有向边到1节点:建一个汇点从n节点…

链接 二分距离,小于当前距离的边容量+1,使最后流>=t 注意 会有重边 #include <iostream> #include<cstdio> #include<cstring> #include<algorithm> #include<stdlib.h> #include<vector> #include<cmath> #include<queue> #include<set> usin…

题目描述 Farmer John is constructing a new milking machine and wishes to keep it secret as long as possible. He has hidden in it deep within his farm and needs to be able to get to the machine without being detected. He must make a total of T (1 <= T <=…

Secret Milking Machine Time Limit: 1000MS   Memory Limit: 65536K Total Submissions: 9658   Accepted: 2859 Description Farmer John is constructing a new milking machine and wishes to keep it secret as long as possible. He has hidden in it deep within…

Description Farmer John is constructing a new milking machine and wishes to keep it secret as long as possible. He has hidden in it deep within his farm and needs to be able to get to the machine without being detected. He must make a total of T (1 <…