费用流+SPFA ||Luogu P3381【模板】最小费用最大流

题面：【模板】最小费用最大流

代码：

 #include<cstdio>
 #include<cstring>
 #include<iostream>
 #include<queue>
 #define ll long long
 #define min(a,b) ((a)<(b)?(a):(b))
 #define max(a,b) ((a)>(b)?(a):(b))
 using namespace std;
 inline ll rd(){
     ll x=,f=;char c=getchar();
     while(c<''||c>''){if(c=='-')f=-; c=getchar();}
     while(c>=''&&c<=''){x=x*+c-''; c=getchar();}
     return f*x;
 }
 const int maxn=,maxm=;
 int N,M,num_edge=-,edge_head[maxn],S,T,u,v,w,f,pre[maxn];
 ll Dis[maxn],Fw[maxn],mxfw,mndis;
 bool vis[maxn];
 queue<int>Q;
 struct Edge{int to,nx,from;ll dis,fw;}edge[maxm<<];
 inline void Add_edge(int from,int to,ll fw,ll dis){
     edge[++num_edge].nx=edge_head[from];
     edge[num_edge].from=from;
     edge[num_edge].to=to;
     edge[num_edge].fw=fw;
     edge[num_edge].dis=dis;
     edge_head[from]=num_edge;
     return;
 }
 inline bool SPFA(){
 //    for(int i=1;i<=N;i++)
 //        Dis[i]=Fw[i]=1ll<<60;
     memset(Dis,0x7f,sizeof(Dis));
     memset(Fw,0x7f,sizeof(Fw));
     memset(vis,,sizeof(vis));
     pre[S]=pre[T]=-;//Imp
     Q.push(S);
     vis[S]=;
     Dis[S]=;
     while(!Q.empty()){
         int x=Q.front();
         Q.pop();
         vis[x]=;
         for(int i=edge_head[x];i!=-;i=edge[i].nx){
             int y=edge[i].to;
             if(edge[i].fw&&edge[i].dis+Dis[x]<Dis[y]){
                 Dis[y]=edge[i].dis+Dis[x];
                 Fw[y]=min(Fw[x],edge[i].fw);//这一步和Dinic差不多
                 pre[y]=i;
                 if(vis[y]==){
                     Q.push(y);
                     vis[y]=;
                 }
             }
         }
     }
     if(pre[T]!=-)return ;
     return ;
 }
 inline void FYL(){
     mxfw=mndis=;
     while(SPFA()){
         mxfw+=Fw[T];
         mndis+=Dis[T]*Fw[T];
         for(int i=pre[T];i!=-;i=pre[edge[i].from]){
             edge[i].fw-=Fw[T];
             edge[i^].fw+=Fw[T];
         }
     }
     return;
 }
 int main(){
     memset(edge_head,-,sizeof(edge_head));
     N=rd();M=rd();S=rd();T=rd();
     for(int i=;i<=M;i++){
         u=rd();v=rd();w=rd();f=rd();
         Add_edge(u,v,w,f);
         Add_edge(v,u,,-f);
     }
     FYL();
     printf("%lld %lld\n",mxfw,mndis);
     return ;
 }

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By:AlenaNuna