poj1459 Power Network

#include<stdio.h>
#include<queue>
#include<string.h>
#define MAXN 1000
#define INF 1<<28

int cap[MAXN][MAXN], vis[MAXN], pre[MAXN], maxflow[MAXN];

using namespace std;

int n, npow, ncon, m;
void bfs()
{
    queue<int>q;
    int i, Maxflow, u, v;
    Maxflow = 0;


    while(1)
    {
        memset(vis, 0, sizeof(vis));
        memset(pre, 0, sizeof(pre));
        memset(maxflow, 0, sizeof(maxflow));

        maxflow[n] = INF;
        q.push(n);

        vis[n] = 1;
        while(!q.empty())
        {
            u = q.front();
            q.pop();
            for(v=0; v<=n+1; v++){
                if(!vis[v] && cap[u][v]>0){
                    vis[v] = 1;
                    pre[v] = u;
                    q.push(v);
                    maxflow[v] = maxflow[u]<cap[u][v]?maxflow[u]:cap[u][v];
                }
            }
        }
        if(!maxflow[n+1]) break;

        for(i=n+1; i!=n; i=pre[i])
        {
            cap[pre[i]][i] -= maxflow[n+1];
            cap[i][pre[i]] += maxflow[n+1];
        }
        Maxflow += maxflow[n+1];
    }
    printf("%d\n", Maxflow);
}

int main()
{
     int i, u, v, c;
     while(~scanf("%d %d %d %d", &n, &npow, &ncon, &m))
     {

         memset(cap, 0, sizeof(cap));

         for(i=0; i<m; i++){
             scanf(" (%d,%d)", &u, &v);
             scanf("%d", &c);
             cap[u][v] += c;
         }

         for(i=0; i<npow; i++){
             scanf(" (%d)", &u);
             scanf("%d", &c);
             cap[n][u] += c;
         }

         for(i=0; i<ncon; i++){
             scanf(" (%d)", &v);
             scanf("%d", &c);
             cap[v][n+1] += c;
         }
         bfs();
     }
     return 0;
}