HDOJ 1789 Doing Homework again贪心

#include"stdio.h"
#include"stdlib.h"
#include"string.h"
typedef struct{
        int score,limit;
        }HWORK;
HWORK a[1001];
int flag[1001];
int cmp(const void *a,const void *b)
{
        return (*(HWORK *)b).score-(*(HWORK *)a).score;
}
main()
{
       int t,n,i,j,ans;
       scanf("%d",&t);
       while(t--) 
       {
                  scanf("%d",&n);
                  memset(flag+1,0,4*n);
                  ans=0;
                  for(i=1;i<=n;i++)scanf("%d",&a[i].limit);
                  for(i=1;i<=n;i++)scanf("%d",&a[i].score);
                  qsort(a+1,n,sizeof(HWORK),cmp);
                  for(i=1;i<=n;i++)
                            if(flag[a[i].limit]==0)
                            {
                                     flag[a[i].limit]=1;
                                     continue;
                            }
                            else{
                                     j=a[i].limit-1;
                                     while(j>0&&flag[j])j--;
                                     if(j==0)ans+=a[i].score;
                                     else flag[j]=1;
                            }
                  printf("%d\n",ans);
       }
       return 0;
}