题目大意是给一张网络,网络可能存在不同边集的最小割,求出拥有最少边集的最小割,最少的边是多少条? 思路:题目很好理解,就是找一个边集最少的最小割,一个方法是在建图的时候把边的容量处理成C *(E+1 )+1,C是初始容量,E是边的个数,假设之前不做此操作处理求得最大流是maxf,处理之后跑dinic求出的最大流就是 maxf *(E+1)+ n , n就代表用了几条边,其中 n 必定是小于 E+1的,这样把处理之后的最大流模上(E+1)得到n,其中n就是最小割的边数,因为每用到一条边得到的最大流…

hdu 6214 Smallest Minimum Cut[最大流] 题意:求最小割中最少的边数. 题解:对边权乘个比边大点的数比如300,再加1 ,最后,最大流对300取余就是边数啦.. #include<iostream> #include<cstdio> #include<cstring> #include<algorithm> #include<cmath> #include<vector> #include<queue…

Smallest Minimum Cut Time Limit: 2000/2000 MS (Java/Others)    Memory Limit: 65535/32768 K (Java/Others)Total Submission(s): 1181    Accepted Submission(s): 473 Problem Description Consider a network G=(V,E) with source s and sink t. An s-t cut is a…

Problem Description Consider a network G=(V,E) with source s and sink t . An s-t cut is a partition of nodes set V into two parts such that s and t belong to different parts. The cut set is the subset of E with all edges connecting nodes in different…

Problem Description Consider a network G=(V,E) with source s and sink t. An s-t cut is a partition of nodes set V into two parts such that s and t belong to different parts. The cut set is the subset of E with all edges connecting nodes in different…

题目链接:http://acm.hdu.edu.cn/showproblem.php?pid=6214 题意:求边数最小的割. 解法: 建边的时候每条边权 w = w * (E + 1) + 1; 这样得到最大流 maxflow / (E + 1) ,最少割边数 maxflow % (E + 1) 道理很简单,如果原先两类割边都是最小割,那么求出的最大流相等 但边权变换后只有边数小的才是最小割了 乘(E+1)是为了保证边数叠加后依然是余数,不至于影响求最小割的结果 因为假设最小割=k,那么现在新…

题意:给定上一个有向图,求 s - t 的最小割且边数最少. 析:设边的容量是w,边数为m,只要把每边打容量变成 w * (m+1) + 1,然后跑一个最大流,最大流%(m+1),就是答案. 代码如下: #pragma comment(linker, "/STACK:1024000000,1024000000") #include <cstdio> #include <string> #include <cstdlib> #include <c…

题目链接 ISAP写法 #include <bits/stdc++.h> using namespace std; typedef long long LL; namespace FastIO { const static int MX=1e6; ; char nc() { static char buf[MX],*p1=buf+MX,*pend=buf+MX; if(p1==pend) { p1=buf; pend=buf+fread(buf,,MX,stdin); if(pend==p1)…

先最大流跑一遍 在残存网络上把满流边容量+1 非满流边容量设为无穷大 在进行一次最大流即可 (这里的边都不包括建图时用于反悔的反向边) #include<cstdio> #include<cstring> #include<cstdlib> #include<queue> #include<iostream> #define rep(i,a,b) for(int i=a;i<=b;++i) using namespace std; ; in…

Consider a network G=(V,E) G=(V,E) with source s s and sink t t . An s-t cut is a partition of nodes set V V into two parts such that s s and t t belong to different parts. The cut set is the subset of E E with all edges connecting nodes in different…