hdu 1285 确定比赛名次

  此题是拓扑排序的典型例子！如果一个队没有前驱就选择，然后去掉以这个点为前驱的点.
   代码：
#include<stdio.h>
#include<string.h>

struct team{
    inte,next;
}ar[20000];

int n,fb[505],num[505];

int search(){//找没有前驱的点
    int i;
   for(i=1;i<=n;i++){
      if(fb[i]==0)
       {
         fb[i]=-1;
          returni;
       }
    }
    return1;
}

void f(int x){//去掉以这个点为前驱的边
    inti,j,k;
   for(i=1;i<=n;i++){
       if(fb[i]&& fb[i]!=-1){
         while(x==ar[fb[i]].e)
          {
            fb[i]=ar[fb[i]].next;
          }
         k=fb[i];
         for(j=ar[fb[i]].next;j;j=ar[j].next){
            if(ar[j].e==x){
                   ar[k].next=ar[j].next;
               continue;
             }
             k=j;
          }
       }
    }
}

void make(){
    inti,x;
   for(i=0;i<n-1;i++){
      x=search();
       printf("%d",x);
       f(x);
    }
   x=search();
   printf("%d\n",x);
}
int main(){
    intm,i,x,y;
   while(scanf("%d%d",&n,&m)!=EOF){
      memset(fb,0,sizeof(fb));
      for(i=1;i<=m;i++){
         scanf("%d%d",&x,&y);
           ar[i].e=x;ar[i].next=fb[y];fb[y]=i;
       }
      make();
    }
    return0;
}