Dinic 模板

 #include <iostream>
 #include <cstring>
 #include <cstdio>
 #include <queue>

 using namespace std;
 const int INF=;
 const int maxn=,maxm=;
 int cnt,fir[maxn],nxt[maxm],cap[maxm],to[maxm],dis[maxn];

 void addedge(int a,int b,int c)
 {
     nxt[++cnt]=fir[a];
     to[cnt]=b;
     cap[cnt]=c;
     fir[a]=cnt;
 }

 bool BFS(int S,int T)
 {
     memset(dis,,sizeof(dis));
     dis[S]=;
     queue<int>q;q.push(S);
     while(!q.empty())
     {
         int node=q.front();q.pop();
         for(int i=fir[node];i;i=nxt[i])
         {
             if(!cap[i]||dis[to[i]])continue;
             dis[to[i]]=dis[node]+;
             q.push(to[i]);
         }
     }
     return dis[T];
 }

 int DFS(int node,int T,int f)
 {
     if(node==T)return f;
     int d,ret=;
     for(int i=fir[node];i;i=nxt[i])
     {
         if(!cap[i]||dis[to[i]]!=dis[node]+)continue;
         if(!f)break;
         d=DFS(to[i],T,min(cap[i],f));
         if(d){
             ret+=d;
             cap[i]-=d;
             cap[i^]+=d;
             f-=d;
         }
     }
     return ret;
 }

 int Dinic(int S,int T)
 {
     int ret=,d;
     while(BFS(S,T)&&(d=DFS(S,T,INF)))
         ret+=d;
     return ret;
 }

 void Init()
 {
     memset(fir,,sizeof(fir));
     cnt=;
 }
 int main()
 {
     int n,m;
     while(~scanf("%d%d",&m,&n))
     {
         Init();
         for(int i=;i<=m;i++){
             int x,y,c;
             scanf("%d%d%d",&x,&y,&c);
             addedge(x,y,c);
             addedge(y,x,);
         }
         printf("%d\n",Dinic(,n));
     }

     return ;
 }