最小费用最大流模板题求助

#include<cstdio>
#include<cstdlib>
#include<cstring>
#include<algorithm>
#include<iostream>
#include<stack>
#include<queue>
#include<vector>
#include<cmath>
#include<map>
#define For(i,a,b) for((i)=(a);(i)<=(b);++(i))
#define Forward(i,a,b) for((i)=(a);(i)>=(b);--(i))
using namespace std;
const int inf=0xFFFFFFF;
inline void read(int &x)
{
    int s=0,f=1;
    char k=getchar();
    while(!isdigit(k)&&k!='-')k=getchar();
    if(k=='-')
    {
        f=-1;
        k=getchar();
    }
    while(isdigit(k))
    {
        s=(s<<3)+(s<<1)+(k^'0');
        k=getchar();
    }
    x=s*f;
}
struct edge
{
    int v,w,next,f;
}p[100000+100];
int n,a[5000+100],m,he[5000+100],s,t,e=1,level[5000+100];
long long fee;
bool vis[5000+100];
void add(int u,int v,int w,int f)
{
    p[++e].v=v;
    p[e].w=w;
    p[e].next=he[u];
    p[e].f=f;
    he[u]=e;
}
queue<int>G;
bool spfa(int s)
{
    fill(level+1,level+n+1,inf);
    memset(vis,0,sizeof(vis));
    level[s]=1;
    G.push(s);
    vis[s]=true;
    while(!G.empty())
    {
        int u=G.front(),v=he[u];
        G.pop();
        while(v)
        {
            if(p[v].w&&level[p[v].v]>level[u]+p[v].f)
            {
                level[p[v].v]=level[u]+p[v].f;
                if(!vis[p[v].v])
                {
                    vis[p[v].v]=true;
                    G.push(p[v].v);
                }
            }
            v=p[v].next;
        }
        vis[u]=false;
    }
    return level[t]!=inf;
}
int dfs(int x,int flow)
{
    if(x==t||!flow)return flow;
    int v=he[x],sum=0;
    while(v)
    {
        if(p[v].w&&level[p[v].v]==level[x]+p[v].f)
        {
            int f=dfs(p[v].v,min(flow,p[v].w));
            fee+=(long long)p[v].f*(long long)f;
            flow-=f;
            p[v].w-=f;
            p[v^1].w+=f;
            sum+=f;
        }
        v=p[v].next;
    }
    return sum;
}
int Dinic(void)
{
    int ans=0;
    while(spfa(s))ans+=dfs(s,inf);
    return ans;
}
int main(void)
{
    int i,j,u,v,w,f;
    read(n);
    read(m);
    read(s);
    read(t);
    For(i,1,m)
    {
        read(u);
        read(v);
        read(w);
        read(f);
        add(u,v,w,f);
        add(v,u,0,0);
    }
    printf("%d",Dinic());
    printf(" %lld\n",fee);
    return 0;
}