int n;
int a[1000010];
int now = 1;

signed main(){
	cin>>n;
	for(int i = 1;i <= n;i ++)a[i] = read();
	sort(a + 1,a + n + 1);
	for(int i = 1;i <= n;i ++)if(a[now] * 2 <= a[i])now ++;
	cout<<n - min(n / 2,now - 1);
}

这样now不会跑到一个已经用过的ai身上？甚至过了CF数据？