POJ 1459 Power Network

很明显的最大流问题，添加超级源点与Power Station相连，超级汇点与Dispatchers相连

 

 

代码：

#include<iostream>using namespace std;int g[105][105],cap[105][105];int ResidualCap[105],pre[105],q[105];int n,np,nc,m,ans;int min(int a,int b){return a<b?a:b;}void update(){int i,min=9999999;/*for(i=n+1;i!=n;i=pre[i]){if(cap[pre[i]][i]-g[pre[i]][i]<min)min=cap[pre[i]][i]-g[pre[i]][i];}*/for(i=n+1;i!=n;i=pre[i]){g[pre[i]][i]+=ResidualCap[n+1];g[i][pre[i]]=-ResidualCap[n+1];}ans+=ResidualCap[n+1];}bool bfs(){int head=0,tail=1,i,j;memset(ResidualCap,0,sizeof(ResidualCap));q[1]=n;ResidualCap[n]=9999999;pre[n]=-1;while(head<tail){head=head+1;j=q[head];for(i=0;i<n+2;i++){if(cap[j][i]>g[j][i]&&!ResidualCap[i]){tail=tail+1;q[tail]=i;pre[i]=j;ResidualCap[i]=ResidualCap[j];if(ResidualCap[i]>cap[j][i]-g[j][i])ResidualCap[i]=cap[j][i]-g[j][i];if(i==n+1)return true;}}}return false;}void EK(){while(bfs())update();}int main(){int i,j,k,a,b,t;while(scanf("%d %d %d %d",&n,&np,&nc,&m)!=EOF){memset(g,0,sizeof(g));memset(c,0,sizeof(c));for(i=1;i<=m;i++){scanf(" (%d,%d)%d",&a,&b,&t);cap[a][b]=t;}for(i=1;i<=np;i++)//添加超级源点{scanf(" (%d)%d",&a,&t);cap[n][a]=t;}for(j=1;j<=nc;j++)//添加超级汇点{scanf(" (%d)%d",&a,&t);cap[a][n+1]=t;}ans=0;EK();printf("%d/n",ans);}return 0;}