标签：
Given an undirected graph, in which two vertexes can be connected by multiple edges, what is the min-cut of the graph? i.e. how many edges must be removed at least to partition the graph into two disconnected sub-graphes?
Input
Input contains multiple test cases. Each test case starts with two integers N and M (2<=N<=500, 0<=M<=N*(N-1)/2) in one line, where N is the number of vertexes. Following are M lines, each line contains M integers A, B and C (0<=A,B<N, A<>B, C>0), meaning that there C edges connecting vertexes A and B.
Output
There is only one line for each test case, which is the min-cut of the graph. If the graph is disconnected, print 0.
Sample Input
3 3 0 1 1 1 2 1 2 0 1 4 3 0 1 1 1 2 1 2 3 1 8 14 0 1 1 0 2 1 0 3 1 1 2 1 1 3 1 2 3 1 4 5 1 4 6 1 4 7 1 5 6 1 5 7 1 6 7 1 4 0 1 7 3 1
Sample Output
2 1 2
/** 最大流 == 最小割 **/ #include <iostream> #include <string.h> #include <cmath> #include <stdio.h> #include <algorithm> using namespace std; typedef long long ll; const int N = 505; const ll maxw = 1000007; const ll inf = 1e17; ll g[N][N], w[N]; int a[N], v[N], na[N]; ll mincut(int n) { int i, j, pv, zj; ll best = inf; for(i = 0; i < n; i ++) { v[i] = i; } while(n > 1) { for(a[v[0]] = 1, i = 1; i < n; i ++) { a[v[i]] = 0; na[i - 1] = i; w[i] = g[v[0]][v[i]]; } for(pv = v[0], i = 1; i < n; i ++) { for(zj = -1, j = 1; j < n; j ++) if(!a[v[j]] && (zj < 0 || w[j] > w[zj])) { zj = j; } a[v[zj]] = 1; if(i == n - 1) { if(best > w[zj]) { best = w[zj]; } for(i = 0; i < n; i ++) { g[v[i]][pv] = g[pv][v[i]] += g[v[zj]][v[i]]; } v[zj] = v[--n]; break; } pv = v[zj]; for(j = 1; j < n; j ++) if(!a[v[j]]) { w[j] += g[v[zj]][v[j]]; } } } return best; } int main() { int n, m, s; while(~scanf("%d %d", &n, &m)) { for(int i = 0; i <= n; i++) { for(int j = 0; j <= n; j++) { g[i][j] = 0; } } int u, v, w; for(int i = 0; i < m; i++) { scanf("%d %d %d", &u, &v, &w); // u--; // v--; g[u][v] += w; g[v][u] += w; } printf("%lld\n", mincut(n)); } return 0; }
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原文地址：http://www.cnblogs.com/chenyang920/p/4725829.html
