IITKWPCO.cpp

#include<stdio.h>
const int MAX = 1000005;
int cnt[MAX];

int main()
{
	int T;
	scanf("%d",&T);
	for(int tc = 0; tc < T; tc++)
	{
		int n;
		scanf("%d",&n);

		for(int i = 0; i < MAX; i++)
			cnt[i] = 0;

		for(int i = 0; i < n; i++)
		{
			int t;
			scanf("%d",&t);
			cnt[t]++;
		}

		int max_collection = 0;
		for(int i = 0; i < MAX; i++)
		{
			if((cnt[i]==0) || (2*i >= MAX) || (cnt[2*i]==0)) continue;
			if(cnt[i] < cnt[2*i])
			{
				max_collection += cnt[i];
				cnt[2*i] -= cnt[i];
			}
			else
			{
				max_collection += cnt[2*i];
				cnt[2*i]= 0;
			}
		}
		printf("%d\n",max_collection);
	}
	return 0;
}