【模板】最小费用最大流

#include<queue>
#include<cstdio>
#include<cstring>
#include<algorithm>
using namespace std;
#define N 5050
#define M 50050
inline int rd()
{
    int f=1,c=0;char ch=getchar();
    while(ch<‘0‘||ch>‘9‘){if(ch==‘-‘)f=-1;ch=getchar();}
    while(ch>=‘0‘&&ch<=‘9‘){c=10*c+ch-‘0‘;ch=getchar();}
    return f*c;
}
int n,m,S,T,hed[N],cnt=-1;
struct EG
{
    int to,nxt,vl,w;
}e[2*M];
void ae(int f,int t,int v,int w)
{
    e[++cnt].to = t;
    e[cnt].nxt = hed[f];
    e[cnt].vl = v;
    e[cnt].w = w;
    hed[f]=cnt;
}
int maxf,minw;
int dis[N],fl[N],pre[N],fa[N];
bool vis[N];
const int inf = 0x3f3f3f3f;
bool spfa()
{
    memset(dis,0x3f,sizeof(dis));
    memset(fl,0,sizeof(fl));
    memset(vis,0,sizeof(vis));
    dis[S]=0,fl[S]=inf,vis[S]=1,pre[T]=-1;
    queue<int>q;
    q.push(S);
    while(!q.empty())
    {
        int u = q.front();
        q.pop();
        vis[u]=0;
        for(int j=hed[u];~j;j=e[j].nxt)
        {
            int to = e[j].to;
            if(e[j].vl&&dis[to]>dis[u]+e[j].w)
            {
                dis[to]=dis[u]+e[j].w;
                fl[to]=min(fl[u],e[j].vl);
                pre[to]=j,fa[to]=u;
                if(!vis[to])
                {
                    vis[to]=1;
                    q.push(to);
                }
            }
        }
    }
    return pre[T]!=-1;
}
void mcmf()
{
    while(spfa())
    {
        minw+=dis[T]*fl[T];
        maxf+=fl[T];
        int tmp = T;
        while(tmp!=S)
        {
            e[pre[tmp]].vl-=fl[T];
            e[pre[tmp]^1].vl+=fl[T];
            tmp=fa[tmp];
        }
    }
}
int main()
{
    n=rd(),m=rd(),S=rd(),T=rd();
    memset(hed,-1,sizeof(hed));
    for(int f,t,v,w,i=1;i<=m;i++)
    {
        f=rd(),t=rd(),v=rd(),w=rd();
        ae(f,t,v,w),ae(t,f,0,-w);
    }
    mcmf();
    printf("%d %d\n",maxf,minw);
    return 0;
}