description: You are given n integers a_1, a_2, …, a_n and an integer k. Find the maximum value of i ⋅ j - k ⋅ (a_i | a_j) over all pairs (i, j) of integers with 1 ≤ i < j ≤ n. Here, | is the [bitwise OR operator](https://en.wikipedia.org/wiki/Bitwise_operation#OR).
  
  Input
  
  The first line contains a single integer t (1 ≤ t ≤ 10 000) — the number of test cases.
  
  The first line of each test case contains two integers n (2 ≤ n ≤ 10^5) and k (1 ≤ k ≤ min(n, 100)).
  
  The second line of each test case contains n integers a_1, a_2, …, a_n (0 ≤ a_i ≤ n).
  
  It is guaranteed that the sum of n over all test cases doesn't exceed 3 ⋅ 10^5.
  
  Output
  
  For each test case, print a single integer — the maximum possible value of i ⋅ j - k ⋅ (a_i | a_j).
  
  Example
  
  Input
  
  
  4
  3 3
  1 1 3
  2 2
  1 2
  4 3
  0 1 2 3
  6 6
  3 2 0 0 5 6
  
  
  Output
  
  
  -1
  -4
  3
  12
  
  Note
  
  Let f(i, j) = i ⋅ j - k ⋅ (a_i | a_j).
  
  In the first test case, 
  
    * f(1, 2) = 1 ⋅ 2 - k ⋅ (a_1 | a_2) = 2 - 3 ⋅ (1 | 1) = -1. 
    * f(1, 3) = 1 ⋅ 3 - k ⋅ (a_1 | a_3) = 3 - 3 ⋅ (1 | 3) = -6. 
    * f(2, 3) = 2 ⋅ 3 - k ⋅ (a_2 | a_3) = 6 - 3 ⋅ (1 | 3) = -3. 
  
  
  
  So the maximum is f(1, 2) = -1.
  
  In the fourth test case, the maximum is f(3, 4) = 12.
solution: import java.io.BufferedReader;
  import java.io.IOException;
  import java.io.InputStreamReader;
  import java.io.PrintWriter;
  
  public class B_Rnd735 
  {
  	public static void main(String[] args) throws NumberFormatException, IOException
  	{
  		BufferedReader scan = new BufferedReader(new InputStreamReader(System.in));
  		PrintWriter out = new PrintWriter(System.out);
  
  		String[] in;
  		int tt = Integer.parseInt(scan.readLine());
  		
  		for(int t = 0; t < tt; t++)
  		{
  			in = scan.readLine().split(" ");
  			int n = parse(in[0]), k = parse(in[1]);
  			
  			in = scan.readLine().split(" ");
  			long[] ray = new long[n];
  			
  			for(int i = 0; i < n; i++)
  				ray[i] = parse(in[i]);
  			
  			long ans = solve(n, k, ray);
  			out.println(ans);
  		}
  
  		out.flush();
  	}
  
  	private static long solve(int n, int k, long[] ray) 
  	{
  		long max = Long.MIN_VALUE;
  		for(int i = n - 1; i >= 0; i--)
  		{
  			if(((long)i + 1) * (i) < max) break;
  			
  			for(int j = i - 1; j >= 0; j--)
  			{
  				max = Math.max(max, ((long) i + 1) * (j + 1) - (k * (ray[i] | ray[j])));
  				if(ray[i] == (ray[i] | ray[j]) || (long) (i + 1) * (long) (j + 1) < max) break;
  			}
  		}
  		
  		return max;
  	}
  
  	public static int parse(String num)
  	{
  		return Integer.parseInt(num);
  	}
  }