[codevs 1993]草地排水

#include<cstdio>#include<queue>#include<cstring>#define maxn 205using namespace std;int n,m;int flow[maxn][maxn],cap[maxn][maxn],d[maxn],father[maxn];queue<int> q;int ans;int main(){scanf("%d%d",&n,&m);int s,e,c;for(int i=1;i<=n;i++){scanf("%d%d%d",&s,&e,&c);cap[s][e]+=c;}for(;;){memset(d,0,sizeof(d));q.push(1);d[1]=1e9;while(!q.empty()){int p=q.front();q.pop();for(int i=1;i<=m;i++){if(!d[i]&&cap[p][i]>flow[p][i]){father[i]=p;d[i]=min(d[p],cap[p][i]-flow[p][i]);q.push(i);}}}if(d[m]==0)break;for(int i=m;i!=1;i=father[i])     {            flow[father[i]][i]+=d[m];            flow[i][father[i]]-=d[m];     }     ans+=d[m];}printf("%d",ans);return 0;}