Spfa费用流模板

const int INF=1000000000;
const int maxn=1010,maxm=400010;
int cnt=1,fir[maxn],nxt[maxm],to[maxm];
int cap[maxm],val[maxm],dis[maxn],path[maxn];

void add(int a,int b,int c,int v){
    nxt[++cnt]=fir[a];to[cnt]=b;
    cap[cnt]=c;val[cnt]=v;fir[a]=cnt;
}
void addedge(int a,int b,int c,int v){
    add(a,b,c,v);
    add(b,a,0,-v);
}

int S,T;
int vis[maxn];
int Spfa(){
    deque<int>q;
    memset(dis,127,sizeof(dis));
    memset(vis,0,sizeof(vis));
    q.push_front(S);
    dis[S]=0;vis[S]=1;
    while(!q.empty()){
        int x=q.front();q.pop_front();vis[x]=0;
        for(int i=fir[x];i;i=nxt[i])
            if(cap[i]&&dis[x]+val[i]<dis[to[i]]){
                dis[to[i]]=val[i]+dis[x];
                path[to[i]]=i;
                if(vis[to[i]])continue;
                if(dis[to[i]]<dis[x])
                    q.push_front(to[i]);
                else
                    q.push_back(to[i]);
                vis[to[i]]=1;    
            }
    }
    return dis[T]==dis[T+1]?0:dis[T]; 
}

int Aug(){
    int p=T,f=INF;
    while(p!=S){
        f=min(f,cap[path[p]]);
        p=to[path[p]^1];
    }
    p=T;
    while(p!=S){
        cap[path[p]]-=f;
        cap[path[p]^1]+=f;
        p=to[path[p]^1];
    }
    return f;
}

int MCMF(){
    int ret=0,d;
    while(d=Spfa())
        ret+=Aug()*d;
    return ret;    
}

#include <queue>
using namespace std;
const int maxn=2010;
const int maxm=500010;
const int INF=1061109567;
int n,m,w[maxn],cnt,fir[maxn],to[maxm],nxt[maxm];
int cap[maxm],val[maxm],path[maxn],vis[maxn],dis[maxn];
queue<int>q;
struct Net_Flow{
    Net_Flow(){cnt=1;}
    
    void add(int a,int b,int c,int v){
        nxt[++cnt]=fir[a];cap[cnt]=c;
        to[cnt]=b;val[cnt]=v;fir[a]=cnt;
    }
    
    void addedge(int a,int b,int c,int v){
        add(a,b,c,v);add(b,a,0,-v);
    }
    
    int Spfa(int S,int T){
        memset(dis,63,sizeof(dis));
        q.push(S);vis[S]=1;dis[S]=0;
        while(!q.empty()){
            int x=q.front();q.pop();vis[x]=0;
            for(int i=fir[x];i;i=nxt[i])
                if(cap[i]&&dis[to[i]]>dis[x]+val[i]){
                    dis[to[i]]=dis[x]+val[i];
                    if(!vis[to[i]])q.push(to[i]);
                    vis[to[i]]=1;path[to[i]]=i;
                }
        }
        return dis[T];
    }
    
    int Aug(int S,int T){
        int p=T,f=INF;
        while(p!=S){
            f=min(f,cap[path[p]]);
            p=to[path[p]^1];
        }p=T;
        while(p!=S){
            cap[path[p]]-=f;
            cap[path[p]^1]+=f;
            p=to[path[p]^1];
        }
        return f;
    }
    
    int MCMF(int S,int T){
        int v=0,d;
        while((d=Spfa(S,T))!=INF)
            v+=d*Aug(S,T);
        return v;
    }
}mcmf;