/* package codechef; // don't place package name! */

import java.util.*;
import java.lang.*;
import java.io.*;

/* Name of the class has to be "Main" only if the class is public. */
public class Codechef
{
	public static void main (String[] args) throws java.lang.Exception
	{
		Scanner sc = new Scanner(System.in);
		int t = sc.nextInt();
		while(t-- > 0) {
		    int n = sc.nextInt();
		    long arr[] = new long[n];
		    for(int i=0; i<n; i++) {
		        arr[i] = sc.nextLong();
		    }
		    long total_sum = 0;
		    for(int i=0; i<n; i++) {
		        total_sum+=arr[i];
		    }
		    long final_sum = total_sum%n;
		    System.out.println((n-final_sum)*final_sum);
		}
	}
}
