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.lang.reflect.Array;
  import java.util.*;
  import java.lang.*;
  import java.io.*;
  public class Solution{
  
      public static void main (String[] args) throws java.lang.Exception {
          FastReader sc = new FastReader();
          int testCase = sc.nextInt();
          BufferedWriter out = new BufferedWriter(new OutputStreamWriter(System.out));
          while (testCase-- > 0) {
              int n = sc.nextInt();
              int k = sc.nextInt();
              int[] intArr = new int[n];
              for(int i=0; i<n; i++){
                  intArr[i]  = sc.nextInt();
              }
              long aa = Long.MIN_VALUE;
              for(int i=Math.max(0, n-2*k); i<n-1; i++){
                  for(int j =i+1; j<n; j++ ){
                      aa=Math.max(aa, (long)(i+1)*(long)(j+1)-k*((long)intArr[i]|(long)intArr[j]));
                  }
              }
              System.out.println(aa);
          }
      }
      // Fast Reader Class
      static class FastReader {
          BufferedReader br;
          StringTokenizer st;
          public FastReader() { br = new BufferedReader(new InputStreamReader(System.in));}
          String next() { while (st == null || !st.hasMoreElements()) { try { st = new StringTokenizer(br.readLine()); } catch (IOException e) { e.printStackTrace(); } }return st.nextToken(); }
          int nextInt() {
              return Integer.parseInt(next());
          }
          long nextLong() {
              return Long.parseLong(next());
          }
          double nextDouble() {
              return Double.parseDouble(next());
          }
          String nextLine() { String str = ""; try { str = br.readLine(); } catch (IOException e) { e.printStackTrace(); }return str; }
      }
  }
  