1020 PAT

在编译器上运行没问题，提交显示编译错误

# include<stdio.h>
# include<stdlib.h>
struct YB
{
    int a,b;
    double c;
}yb[];

int cmp( const void *a ,const void *b)
{
   return (*(YB *)a).c > (*(YB *)b).c ? - : ;
}  

int main()
{
    int N,D,i;
    double sum;
    scanf("%d %d",&N,&D);
    for(i=;i<N;i++)
    {
        scanf("%d",&yb[i].a);
    }
    for(i=;i<N;i++)
    {
        scanf("%d",&yb[i].b);
    }
    for(i=;i<N;i++)
    {
        yb[i].c = yb[i].b *1.0 /  yb[i].a;
    }

    qsort(yb,N,sizeof(yb[]),cmp);

     for(i=;;i++)
     {
         if(D - yb[i].a <= )
         {
             break;
        }

        sum = sum + yb[i].b;
        D = D - yb[i].a;
    }

    sum = sum + D*yb[i].c;

    printf("%.2lf",sum);
    return ;
}