poj 3637 Shopaholic

#include<iostream>#include<algorithm>using namespace std;int main(){ int num[20010]; int n,t; scanf("%d",&t); while(t--) {  int sum=0;  scanf("%d",&n);  for(int i=0;i<n;++i)   scanf("%d",&num[i]);  sort(num,num+n);  if(n<3)   printf("0n");  else  {   for(int i=n-3;i>=0;i-=3)   {    sum+=num[i];   }   printf("%dn",sum);  } } return 0;}