最小费用最大流

邻接矩阵+SPFA

bool spfa(){
    int u,v;
    memset(pre,0,sizeof pre);
    memset(dist,0x7f,sizeof dist);
    dist[S]=0;
    vis[S]=1;
    q.push(S);
    while(!q.empty()){
        u=q.front();
        q.pop();
        vis[u]=0;
        for(v=S;v<=T;v++)
            if(cap[u][v].c&&dist[v]>cap[u][v].wt+dist[u]){
                dist[v]=cap[u][v].wt+dist[u];
                pre[v]=u;
                if(!vis[v]){
                    vis[v]=1;
                    q.push(v);
                }
            }
    }
    if(dist[T]==INF)
        return 0;
    else
        return 1;
}
void mcmf(){
    int delta,p;
    while(spfa()){
        delta=INF;
        for(p=T;pre[p];p=pre[p])
            delta=min(delta,cap[pre[p]][p].c);
        for(p=T;pre[p];p=pre[p]){
            cost+=cap[pre[p]][p].wt*delta;
            cap[pre[p]][p].c-=delta;
            cap[p][pre[p]].c+=delta;
        }
    }
}

邻接表+SPFA(SLF+LLL)

bool spfa(){
    memset(dist,0x7f,sizeof dist);
    int u,v,len,cnt;
    len=cnt=0;
    q.push_back(S);
    vis[S]=1;
    dist[S]=0;
    while(!q.empty()){
        u=q.front();
        q.pop_front();
        if(dist[u]*len>cnt){
            q.push_back(u);
            continue;
        }
        vis[u]=0;
        len--,cnt-=dist[u];
        for(node *p=adj[u];p;p=p->next){
            v=p->v;
            if(p->cap&&dist[v]>dist[u]+p->wt){
                pre[v]=p;
                if(vis[v])
                    cnt-=dist[v];
                dist[v]=dist[u]+p->wt;
                cnt+=dist[v];
                if(!vis[v]){
                    if(q.empty()||dist[v]>dist[q.front()])
                        q.push_back(v);
                    else
                        q.push_front(v);
                    vis[v]=1;
                    len++;
                }
            }
        }
    }
    if(dist[T]==INF)
        return 0;
    return 1;
}
void mcmf(){
    int u,delta;
    while(spfa()){
        delta=INF;
        for(u=T;u!=S;u=pre[u]->back->v)
            delta=min(delta,pre[u]->cap);
        for(u=T;u!=S;u=pre[u]->back->v){
            cost+=delta*pre[u]->wt;
            pre[u]->cap-=delta;
            pre[u]->back->cap+=delta;
        }
    }
}