Sum of bit difference [MEDIUM]

Company: Google

Question:

Write a program to find the sum of bit differences in all pairs that can be formed from array elements n. Bit difference of a pair (x, y) is a count of different bits at same positions in binary representations of x and y. For example, bit difference for 2 and 7 is 2. Binary representation of 2 is 010 and 7 is 111 ( first and last bits differ in two numbers).

Input: The first line of input contains an integer T denoting the number of test cases. First line of the test case will contain an array of elements n.
Output: The sum of bit differences of all pairs that can be formed by given array.
Constraints:

1 <=T<= 100

1 <=N<= 10

1 <=a[i]<= 10
Example:

Input:

2
2 
1 2
3 
1 3 5

Output:

4

8

CODE:

import java.util.*;

import java.lang.*;

import java.io.*;

class Solution

 {

public static void main (String[] args)

{

  Scanner sc = new Scanner(System.in);

   int t = sc.nextInt();

   sc.nextLine();

   

   while(t-->0){

       int n = sc.nextInt();

       int a[]=new int[n];

       for(int i=0;i<n;i++)

       a[i]=sc.nextInt();

       int c=0;

       for(int i=0;i<n-1;i++){

           for(int j=i+1;j<n;j++){

               c+=sum(a[i],a[j]);

           }

       }

        System.out.println(2*c);

   }

}

 

static int sum(int n, int m){

        int q=m^n;

        int c=0;

        while(q>0){

            c+=q%2;

            q/=2;

        }

        return c;

}

}

Execution Time:0.12