hdu 3549 Flow Problem(图论:网络流增广路)

#include <queue>
#include <cstdio>
#include <cstring>
#include <iostream>
#include <algorithm>
#define MAXN 2000
#define LL long long
#define INF 0x7fffffff
using namespace std;

int n;
int flow[20][20], p[MAXN];
int a[MAXN], cap[20][20];

int Karp(int s, int t) {
queue<int> q;
memset(flow, 0, sizeof(flow));
int f = 0;
while(true) {
memset(a, 0, sizeof(a));
a[s] = INF;
q.push(s);
while(!q.empty()) {
int u = q.front();
q.pop();
for(int v=1; v<=n; ++v) {
if(!a[v] && cap[u][v]>flow[u][v]) {
p[v] = u;
q.push(v);
a[v] = min(a[u], cap[u][v]-flow[u][v]);
}
}
}
if(a[t] == 0)
break;
for(int u=t; u!=s; u=p[u]) {
flow[p[u]][u] += a[t];
flow[u][p[u]] -= a[t];
}
f += a[t];
}
return f;
}

int main(void) {
int T, m, x, y, t, w;
scanf("%d", &T);
for(t=1; t<=T; ++t) {
scanf("%d%d", &n, &m);
memset(cap, 0, sizeof(cap));
while(m--) {
scanf("%d%d%d", &x, &y, &w);
cap[x][y] += w;
}
printf("Case %d: %d\n", t, Karp(1, n));
}
return 0;
}