最小费用最大流( spfa )

 

const int N =5005, M=1e5+100;

 #define inf 1e9
 int all=1,hd[N],go[M],w[M],nxt[M],cost[M];
 
 int S,T,n,m;
 int pre[N],mn[N],dis[N],vis[N],ans=0;
 
 void add_(int x,int y,int z,int c){
     nxt[++all]=hd[x]; hd[x]=all; go[all]=y;
     w[all]=z; cost[all]=c;
     
     swap(x,y);
     nxt[++all]=hd[x]; hd[x]=all; go[all]=y;
     w[all]=0; cost[all]= -c; 
 }
 
 bool spfa(){
 	int i;
 	queue<int> q;
 	q.push(S);
 	for(i=0;i<N;i++) dis[i]=inf;
 	for(i=1;i<N;i++) vis[i]=0;
 	mn[S]=inf, dis[S]=0, vis[S]=1;
 	
 	while(!q.empty()){
 		int x=q.front();
 		vis[x]=0;
 		q.pop();
 		for(i=hd[x];i;i=nxt[i]){
 			int y=go[i],z=w[i],c=cost[i];
 			if(w[i]==0) continue; 
 			
 			if(dis[x]+c<dis[y]){
 				dis[y]=dis[x]+c;
 				mn[y]=min(mn[x],z);
 				pre[y]=i;
 				if(vis[y]==0) vis[y]=1,q.push(y);
 			}
 		}
 	}
 	if(dis[T]==inf) return 0; return 1;
 }
 void solve(){
 	int maxf=0, minc=0;
 	while(spfa()){
 		int x= T;
 		maxf+=  mn[T] ,minc+= mn[T]*dis[T];
 		
 		while(x!=S){
 			int i=pre[x];
 			w[i]-= mn[T];
 			w[i^1]+=mn[T];
 			x=go[i^1];
 		}
 	}
 	cout<<maxf<<' '<<minc<<endl;
 }