最小费用最大流MCMF zkw费用流

稀疏图慢死了。。。但是稠密图效果还是很好的

 struct MCMF{
     struct tedge{int x,y,cap,w,next;}adj[maxm];int ms,fch[maxn];
     int vis[maxn],d[maxn],ans,cost,S,T,n;
     void init(int n){
         this->n=n;ms=;ans=cost=;
         memset(fch,-,sizeof(fch));
         return;
     }
     inline void addedge(int u,int v,int cap,int w){
         adj[ms]=(tedge){u,v,cap,w,fch[u]};fch[u]=ms++;
         adj[ms]=(tedge){v,u,,-w,fch[v]};fch[v]=ms++;
         return;
     }
     inline int aug(int u,int f){
         if(u==T){ans+=cost*f;return f;}
         int tmp=f;vis[u]=;
         for(int i=fch[u];i!=-;i=adj[i].next){
             int v=adj[i].y;
             if(adj[i].cap&&!adj[i].w&&!vis[v]){
                 int a=aug(v,tmp<adj[i].cap?tmp:adj[i].cap);
                 adj[i].cap-=a;
                 adj[i^].cap+=a;
                 tmp-=a;
                 if(!tmp) return f;
             }
         } return f-tmp;
     }
     inline bool spfa(){
         for(int i=;i<=n;i++) d[i]=inf;
         deque<int>Q;Q.push_back(T);d[T]=;
         while(!Q.empty()){
             int u=Q.front(),tmp;Q.pop_front();
             for(int i=fch[u];i!=-;i=adj[i].next)
                 if(adj[i^].cap&&(tmp=d[u]-adj[i].w)<d[adj[i].y])
                     (d[adj[i].y]=tmp)<=d[Q.empty()?S:Q.front()]?Q.push_front(adj[i].y):Q.push_back(adj[i].y);
         }
         for(int u=;u<=n;u++)
             for(int i=fch[u];i!=-;i=adj[i].next)
                 adj[i].w+=d[adj[i].y]-d[u];
         cost+=d[S];return d[S]<inf;
     }
     int costflow(int S,int T){
         this->S=S;this->T=T;
         while(spfa())do memset(vis,false,sizeof(vis));while(aug(S,inf));
         return ans;
     }
 }sol;

搜索

复制