poj 1273

网络流最基础的题目，最大流

#include <iostream>#include <cstring>#include <queue>using namespace std;const int maxn=210;const int inf=1<<30;int cap[maxn][maxn],flow[maxn][maxn],d[maxn];int n,m,tot;void ek(){int q[maxn],p[maxn],i;int front,rear;for(;;){memset(d,0,sizeof(d));front=rear=0;q[rear++]=1;d[1]=inf;while(rear-front>0){int u=q[front];for(i=1;i<=m;i++){if(!d[i]&&cap[u][i]>flow[u][i]){p[i]=u;q[rear++]=i;d[i]=d[u]>(cap[u][i]-flow[u][i])?(cap[u][i]-flow[u][i]):d[u];}}front++;}if(!d[m]) break;int tem;for(tem=m;tem!=1;tem=p[tem]){flow[p[tem]][tem]+=d[m];flow[tem][p[tem]]-=d[m];}tot+=d[m];}return;}int main(){while(cin>>n>>m){int i,u,v,f;tot=0;memset(cap,0,sizeof(cap));memset(flow,0,sizeof(flow));for(i=0;i<n;i++){cin>>u>>v>>f;cap[u][v]+=f;}ek();cout<<tot<<endl;}return 0;}