Average Numbers BIT1001

大水题

#include<iostream>
#include<algorithm>
#include<cstdio>
int a[300000];
int res[300000];
int main()
{
	int total;
	scanf("%d",&total);
	while(total--)
	{
		long long sum=0;
		int n;
		scanf("%d",&n);
		for(int i=1;i<=n;i++)
		{
			scanf("%d",&a[i]);
			sum+=a[i];
		}
		if(sum%n!=0)
		{
			printf("0\n");
			continue;
		}
		sum/=n;
		int counter=0;
		for(int i=1;i<=n;i++)
		{
			if(sum==a[i])
			{
				res[counter++]=i;
			}
		}
		if(counter==0)
		{
			printf("0\n");
			continue;
		}
		printf("%d\n",counter);
		for(int i=0;i<counter-1;i++)
		{
			printf("%d ",res[i]);
		}
		printf("%d\n",res[counter-1]);
	}
	return 0;
}