
import java.util.*;
import java.io.*;
import javafx.util.Pair;

public class One {

    static BufferedReader bf = new BufferedReader(new InputStreamReader(System.in));
    static StringBuilder out = new StringBuilder();
    static BufferedWriter bw = new BufferedWriter(new OutputStreamWriter(System.out));
    static PrintWriter pw = new PrintWriter(new OutputStreamWriter(System.out));

    static int I(String s) {
        return Integer.parseInt(s);
    }

    static long L(String s) {
        return Long.parseLong(s);
    }

    static double D(String s) {
        return Double.parseDouble(s);
    }

    static String[] SA() throws IOException {
        return bf.readLine().split(" ");
    }

    public static void main(String[] args) throws IOException {
        int t = I(bf.readLine());
        while (t-- > 0) {
               long n = I(bf.readLine());
            StringTokenizer in = new StringTokenizer(bf.readLine());
           long x=0l;
           for(int i=0;i<n;i++){
           x+=L(in.nextToken());
           }
          long mod=x%n;
           
            System.out.println(mod*(mod-n));
        }

    }

}
