//求網(wǎng)絡(luò)最大流,鄰接表形式
//返回最大流量,flow返回每條邊的流量
//傳入網(wǎng)絡(luò)節(jié)點數(shù)n,容量mat,源點source,匯點sink

#define MAXN 100
#define inf 1000000000

int max_flow(int n,int mat[][MAXN],int source,int sink,int flow[][MAXN]){
	int pre[MAXN],que[MAXN],d[MAXN],p,q,t,i,j,r;
	vector<int> e[MAXN];	
	if (source==sink) return inf;
	for (i=0;i<n;i++)
		for (j=0;j<n;flow[i][j++]=0);
	//e[i]存放所有以i相鄰的點,包括反向邊!!!
	for (i=0;i<n;i++)
		for (e[i].clear(),j=0;j<n;j++)
			if (mat[i][j]) e[i].push_back(j),e[j].push_back(i);
	for (;;){
		for (i=0;i<n;pre[i++]=0);
		pre[t=source]=source+1,d[t]=inf;
		for (p=q=0;p<=q&&!pre[sink];t=que[p++])
			for (r=0;r<e[t].size();++r){
				i=e[t][r];			
				if (!pre[i]&&(j=mat[t][i]-flow[t][i]))
					pre[que[q++]=i]=t+1,d[i]=d[t]<j?d[t]:j;
				else if (!pre[i]&&(j=flow[i][t]))
					pre[que[q++]=i]=-t-1,d[i]=d[t]<j?d[t]:j;
			}
		if (!pre[sink]) break;
		for (i=sink;i!=source;)
			if (pre[i]>0)
				flow[pre[i]-1][i]+=d[sink],i=pre[i]-1;
			else
				flow[i][-pre[i]-1]-=d[sink],i=-pre[i]-1;
	}
	for (j=i=0;i<n;j+=flow[source][i++]);
	return j;
}