ZKW费用流修正

 #include<iostream>
 #include<cstdio>
 #include<cmath>
 #include<algorithm>
 #include<stack>
 #include<queue>
 #include<cstring>
 #define PAU putchar(' ')
 #define ENT putchar('\n')
 #define MSE(a,b) memset(a,b,sizeof(a))
 #define REN(x) for(ted*e=fch[x];e;e=e->nxt)
 #define TIL(x) for(int i=1;i<=x;i++)
 using namespace std;
 const int maxn=+,maxm=+,inf=1e9;
 struct zkw{
     struct ted{int x,y,w,c;ted*nxt,*re;}adj[maxm],*fch[maxn],*ms;
     int n,S,T,d[maxn],cost,ans;bool inq[maxn],vis[maxn];
     void init(int n){this->n=n;ms=adj;MSE(vis,false);MSE(inq,false);return;}
     void add(int x,int y,int w,int c){
         *ms=(ted){x,y,w,c,fch[x],ms+};fch[x]=ms++;
         *ms=(ted){y,x,,-c,fch[y],ms-};fch[y]=ms++;
         return;
     }
     bool bfs(){
         TIL(n)d[i]=inf;queue<int>Q;Q.push(T);d[T]=;
         while(!Q.empty()){
             int x=Q.front();Q.pop();inq[x]=false;REN(x){
                 int v=e->y;if(e->re->w&&d[v]>d[x]+e->re->c){
                     d[v]=d[x]+e->re->c;if(!inq[v])inq[v]=true,Q.push(v);
                 }
             }
         }for(ted*e=adj;e!=ms;e++)e->c+=d[e->y]-d[e->x];cost+=d[S];return d[S]!=inf;
     }
     int dfs(int x,int aug){
         if(x==T||!aug)return(ans+=aug*cost,aug);int flow=,k;vis[x]=true;REN(x){
             int v=e->y;if(e->w&&!e->c&&!vis[v]&&(k=dfs(v,min(aug,e->w)))){
                 e->w-=k;e->re->w+=k;flow+=k;aug-=k;if(!aug)break;
             }
         }return flow;
     }
     int mcmf(int S,int T){
         this->S=S;this->T=T;while(bfs())do MSE(vis,false);while(dfs(S,inf));return ans;
     }
 }sol;
 inline int read(){
     int x=,sig=;char ch=getchar();
     for(;!isdigit(ch);ch=getchar())if(ch=='-')sig=;
     for(;isdigit(ch);ch=getchar())x=*x+ch-'';
     return sig?x:-x;
 }
 inline void write(int x){
     if(x==){putchar('');return;}if(x<)putchar('-'),x=-x;
     int len=,buf[];while(x)buf[len++]=x%,x/=;
     for(int i=len-;i>=;i--)putchar(buf[i]+'');return;
 }
 int n,m;
 int main(){
     n=read();m=read();sol.init(n);int x,y,w;
     TIL(m)x=read(),y=read(),w=read(),sol.add(x,y,w,read());write(sol.mcmf(,n));
     return ;
 }