最大流模板2

    #include <iostream>  
    #include <queue>  
    using namespace std;  
      
    #define min(a,b) (a)<(b)?a:b  
    #define N 16  
    int capacity[N][N]; //容量  
    int flow[N]; //残余容量  
    int pre[N]; //前驱结点  
    int n,m;  
    queue<int> qu;  
      
    int BFS(int src,int des)  
    {  
        while(!qu.empty())  
            qu.pop();  
        for(int i=1;i<=n;i++)  
            pre[i]=-1;  
        pre[src]=0;  
        flow[src]=INT_MAX; //初始化源点的流量为无穷  
        qu.push(src);  
        while(!qu.empty())  
        {  
            int index=qu.front();  
            qu.pop();  
            if(index == des)  
                break;  
            for(i=1;i<=n;i++)  
            {  
                if(i!=src && capacity[index][i]>0 && pre[i] == -1)  
                {  
                    pre[i]=index;  
                    flow[i]=min(capacity[index][i],flow[index]);  
                    //一步步找出增广路径中的最小的可增加流量  
                    qu.push(i);  
                }  
          }  
        }  
        if(pre[des] == -1)  
            return -1; //不存在增广路径  
        return flow[des];  
    }  
      
    int MaxFlow(int src,int des)  
    {  
        int aug=0;  
        int sumflow=0;  
        while((aug=BFS(src,des)) != -1)  
        {  
            int k=des;  
            while(k!=src)  
            {  
                int last=pre[k];  
                capacity[last][k] -= aug;  
                capacity[k][last] += aug;  
                k=last;  
            }  
            sumflow += aug;  
        }  
        return sumflow;  
    }  
      
    int main()  
    {  
        int nCase,cas=1;  
        cin>>nCase;  
        while(nCase--)  
        {  
            cin>>n>>m;  
            memset(capacity,0,sizeof(capacity));  
            memset(flow,0,sizeof(flow));  
            for(int i=0;i<m;i++)  
            {  
                int u,v,w;  
                cin>>u>>v>>w;  
                if(u == v)  
                    continue;  
                capacity[u][v] +=w;  
            }  
            cout<<"Case "<<cas++<<": "<<MaxFlow(1,n)<<endl;  
        }  
        return 0;