【最大流FF模板】HDU1532&POJ1273

参照《挑战程序设计竞赛》

#include<iostream>
#include<cstdio>
#include<cstdlib>
#include<cstring>
#include<algorithm>
#include<cmath>
#include<vector>
using namespace std;
const int MAXN=1100;
const int INF=0x7fffffff;
int n,m;//n:edges,m:points 
struct node
{
       int to,pos,cap;
};
vector<node> E[MAXN];
int vis[MAXN];

void addedge(int u,int v,int w)
{
     E[u].push_back((node){v,E[v].size(),w});
     E[v].push_back((node){u,E[u].size()-1,0});
}

int dfs(int s,int t,int f)
{
    if (s==t) return f;
    vis[s]=1;//不要忘记这里要设置为访问过 
    for (int i=0;i<E[s].size();i++)
    {
        node &tmp=E[s][i]; 
        if (vis[tmp.to]==0 && tmp.cap>0)
        {
            int delta=dfs(tmp.to,t,min(tmp.cap,f));
            if (delta>0)
            {
               tmp.cap-=delta;
               E[tmp.to][tmp.pos].cap+=delta;
               return delta; 
            }
        }
    }
    return 0;
}

int maxflow(int u,int v)
{
    int flow=0;
    for (;;)
    {
        memset(vis,0,sizeof(vis));
        int f=dfs(u,v,INF);
        if (f==0) return flow;
           else flow+=f; 
    }
}

int main()
{
    while(~scanf("%d%d",&n,&m))
    {
          memset(E,0,sizeof(E));
          for (int i=0;i<n;i++)
          {
              int x,y,z;
              scanf("%d%d%d",&x,&y,&z);
              addedge(x,y,z);
          }
          cout<<maxflow(1,m)<<endl;
    }
    return 0;
}