网络流--最小费用最大流MCMF模板

标准大白书式模板

#include<stdio.h>        //大概这么多头文件昂
#include<string.h>
#include<vector>
#include<queue>
#include<algorithm>
using namespace std;
const int maxm=10000+100;    //最大点数
const int INF=0x3f3f3f3f;

struct edge{        //边：起点、终点、容量、流量、单位费用
    int from,to,c,f,cost;
    edge(int a,int b,int m,int n,int p):from(a),to(b),c(m),f(n),cost(p){}
};

int aabs(int a){
    return a>=0?a:-a;
}

struct MCMF{
    int m,s,t;
    vector<edge>e;
    vector<int>g[maxm];
    int dis[maxm],a[maxm],p[maxm];
    bool vis[maxm];

    void init(int n){        //初始化函数
        for(int i=0;i<=n;i++)g[i].clear();
        e.clear();
    }

    void add(int a,int b,int c,int v){    //加边函数
        e.push_back(edge(a,b,c,0,v));
        e.push_back(edge(b,a,0,0,-v));
        m=e.size();
        g[a].push_back(m-2);
        g[b].push_back(m-1);
    }

    bool spfa(int& flow,int& cost){
        memset(dis,0x3f,sizeof(dis));
        memset(vis,0,sizeof(vis));
        queue<int>q;
        q.push(s);
        vis[s]=1;
        dis[s]=0;
        p[s]=0;
        a[s]=INF;
        while(!q.empty()){
            int u=q.front();q.pop();
            vis[u]=0;
            for(int i=0;i<g[u].size();i++){
                edge tmp=e[g[u][i]];
                if(dis[tmp.to]>dis[u]+tmp.cost&&tmp.c>tmp.f){
                    dis[tmp.to]=dis[u]+tmp.cost;
                    p[tmp.to]=g[u][i];
                    a[tmp.to]=min(a[u],tmp.c-tmp.f);
                    if(!vis[tmp.to]){
                        q.push(tmp.to);
                        vis[tmp.to]=1;
                    }
                }
            }
        }
        if(dis[t]==INF)return 0;
        flow+=a[t];
        cost+=dis[t]*a[t];
        int u=t;
        while(u!=s){
            e[p[u]].f+=a[t];
            e[p[u]^1].f-=a[t];
            u=e[p[u]].from;
        }
        return 1;
    }

    int MF(int s,int t){        调用的计算最小费用函数
        this->s=s;this->t=t;
        int flow=0,cost=0;
        while(spfa(flow,cost));
        return cost;
    }

};