最小费用最大流模板

好久没写网络流，今天放一套费用流模板在这。

---

 

#include<bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef pair<int,int> PII;
#define ls l,mid,rt<<1
#define rs mid+1,r,rt<<1|1
#define endl '\n'
#define p4 puts("444")
const int N = 5e3+10,M = 5e4+10;
const double EPS = 1e-12;
const ll mod = 1e9+7;

int n,m,s,t,cnt;
ll maxflow,cost;
int head[N],cur[N],inq[N];
ll dis[N];
int book[N];
struct edge{
    int to,next,cap;
    ll cost;
}E[M<<1];
struct node{
    inline void Add(int u,int v,int w,ll c){
        E[cnt].to=v;
        E[cnt].cap=w;
        E[cnt].next=head[u];
        E[cnt].cost=c;
        head[u]=cnt++;
    }
    inline bool Spfa(){
        for(int i=1;i<=n;i++)cur[i]=head[i],dis[i]=1e18,inq[i]=0;
        queue<int>que;
        que.push(s);
        inq[s]=1;
        dis[s]=0;
        while(!que.empty()){
            int u=que.front();que.pop();
            inq[u]=0;
            for(int i=head[u];~i;i=E[i].next){
                int v=E[i].to;
                if(E[i].cap&&dis[v]>dis[u]+E[i].cost){
                    dis[v]=dis[u]+E[i].cost;
                    if(!inq[v]){
                        inq[v]=1;
                        que.push(v);
                    }
                }
            }
        }
        return dis[t]==1e18 ? 0 : 1;
    }
    inline int dfs(int u,int flow){
        int rlow=0;
        if(u==t){
            book[t]=1;
            maxflow+=flow;
            return flow;
        }
        int used=0;
        book[u]=1;
        for(int i=cur[u];~i;i=E[i].next){
            cur[u]=i;
            int v=E[i].to;
            if((!book[v]||v==t)&&E[i].cap&&dis[v]==dis[u]+E[i].cost){
                if(rlow=dfs(v,min(flow-used,E[i].cap))){
                    used+=rlow;
                    cost+=rlow*E[i].cost;
                    E[i].cap-=rlow;
                    E[i^1].cap+=rlow;
                    if(used==flow)break;
                }
            }
        }
        return used;
    }
    inline void Solve(){
        while(Spfa()){
            book[t]=1;
            while(book[t]){
                memset(book,0,sizeof(book));
                dfs(s,1e9);
            }
        }
    }
}Dinic;

int main()
{
    maxflow=cost=cnt=0;
    scanf("%d %d %d %d",&n,&m,&s,&t);
    memset(head,-1,sizeof(head));
    int u,v,w; ll c;
    for(int i=1;i<=m;i++){
        scanf("%d %d %d %lld",&u,&v,&w,&c);
        Dinic.Add(u,v,w,c); Dinic.Add(v,u,0,-c);
    }
    Dinic.Solve();
    printf("%lld %lld",maxflow,cost);
}