poj 1966 Cable TV Network 点连通度

#include <stdio.h>
#include <string.h>
#define Max 300
#define INF 5000000
int flow[Max][Max],d[Max];
int map[Max][Max];
int sta,end; 
int m,n;
int min(int a,int b)
{
    if(a<b) return a;
    else return b;
}
bool bfs(int s)
{
    int front=0,rear=0; 
    int q[Max*100];
    int k,i;
    memset(d,-1,sizeof(d)); 
    q[rear++]=s;  d[s]=0;
    while(front<rear)
    {
        k=q[front++];
		if(k==end) break;
        for(i=1;i<=2*n;i++)
            if(flow[k][i]>0&&d[i]==-1)
            {
                d[i]=d[k]+1;
                q[rear++]=i;
            }
    }
    if(d[end]>=0)   return true;
    return false;
}

int dinic(int k,int sum)
{
    int i,a;
    if(k==end)    return sum;
    int os=sum;
    for(i=1;i<=2*n&∑i++)
        if(d[i]==d[k]+1&&flow[k][i]>0)
        {
            a=dinic(i,min(sum,flow[k][i])); 
            flow[k][i]-=a;
            flow[i][k]+=a;
            sum-=a;
        }
    return os-sum;
}


int main()
{
	int x,y;
	while(scanf("%d%d",&n,&m)!=EOF)
	{
		memset(map,0,sizeof(map));
		int i,j,k;
		for(i=1;i<=n;i++) map[i][i+n]=1;
		for(i=1;i<=m;i++)
		{
			scanf(" (%d,%d)",&x,&y);
			x++;y++;
			map[y+n][x]=INF;
			map[x+n][y]=INF;
		}
		int ans=INF;
		int now;
		sta=n+1;
		for(i=2;i<=n;i++)
		{
			for(k=1; k <= 2*n; k++)
				for(j=1; j <= 2*n; j++)
					flow[k][j]=map[k][j];
			end=i;
			now=0;
			while(bfs(sta))
				now+=dinic(sta,INF);
			if(now<ans) ans=now;
		}
		if(ans>=INF) printf("%d
",n);
		else printf("%d
",ans);
	}
	return 0;
}