最小费用最大流

#include<cstdio> 
#include<cstring>
#include<cmath>
#include<ctime>
#include<iostream>
#include<algorithm>
#include<queue>
#include<set>
#define maxint (2147483647)
#define l(a) ((a)<<1)
#define r(a) ((a)<<1|1)
#define b(a) (2<<(a))
#define rep(i,a,b) for(int i=a;i<=(b);i++)
#define Rep(e,x) for(edge*e=fir[x];e;e=e->next)
#define clr(a) memset(a,0,sizeof(a))
typedef long long ll;
using namespace std;
int readint(){
    int t=0,f=1;char c=getchar();
    while(!isdigit(c)){
        if(c=='-') f=-1;
        c=getchar();
    }
    while(isdigit(c)){
        t=(t<<3)+(t<<1)+c-'0';
        c=getchar();
    }
    return t*f;
}
const int maxn=5009,maxm=50009;
int n,m,S,T,flow,cost,d[maxn],a[maxn];
bool p[maxn];
struct edge{
    int v,w,c;
    edge*next,*r;
}e[maxm<<2],*fir[maxn],*cur[maxn],*pre[maxn],*pt=e;
void add(int u,int v,int w,int c){
    pt->v=v;pt->w=w;pt->c=c;
    pt->next=fir[u];fir[u]=pt++;
}
void addedge(int u,int v,int w,int c){
    add(u,v,w,c);add(v,u,0,-c);
    fir[u]->r=fir[v];fir[v]->r=fir[u];
}
bool spfa(){
    queue<int>Q;Q.push(S);clr(p);p[S]=1;
    rep(i,1,n) d[i]=maxint;d[S]=0;clr(a);a[S]=maxint;
    while(!Q.empty()){
        int x=Q.front();Q.pop();p[x]=0;
        Rep(e,x) if(e->w) if(d[e->v]>d[x]+e->c){
            d[e->v]=d[x]+e->c;    
            a[e->v]=min(a[x],e->w);
            pre[e->v]=e;
            if(!p[e->v]){
                Q.push(e->v);
                p[e->v]=1;
            }
        }
    }
    return d[T]!=maxint;
}
void cal(){
    while(spfa()){
        flow+=a[T];cost+=a[T]*d[T];
        for(edge*e=pre[T];e;e=pre[e->r->v]){
            e->w-=a[T];e->r->w+=a[T];
        }
    }
}
int main(){
    //freopen("#intput.txt","r",stdin);
    //freopen("#output.txt","w",stdout);
    n=readint();m=readint();S=readint();T=readint();
    rep(i,1,m){
        int u=readint(),v=readint(),w=readint(),c=readint();
        addedge(u,v,w,c);
    }
    cal();
    printf("%d %d
",flow,cost);
    //fclose(stdin);
    //fclose(stdout);
    return 0;
}