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.util.*;
  
  
  
  import static javax.swing.UIManager.get;
  import static javax.swing.UIManager.getString;
  
  
  public class Main {
  
  
      static class Pair implements Comparable<Pair>{
          int x=0;
          int y=0;
          public Pair(int x1,int y1)
          { x=x1;
              y=y1;
          }
  
  
          @Override
          public int compareTo(Pair o) {
              return this.x-o.x;
          }
      }
  
      static boolean checkPallindrome(int n)
      {    ArrayList<Integer> list = new ArrayList<>();
          while(n>0)
          { list.add(n%10);
              n/=10;
          }
          int low=0,high=list.size()-1;
          while(low<=high)
          {     if(list.get(low)!=list.get(high))
              return false;
              low++;
              high--;
          }
          return true;
      }
  
  
      static boolean check(String s)
      {
  
          int low=0,high=s.length()-1;
          while(low<=high)
          {     if(s.charAt(low)!=s.charAt(high))
              return false;
              low++;
              high--;
          }
          return true;
      }
  
      class Node implements Comparable<Node>{
        int x=0,y=0,z=0;
          @Override
          public int compareTo(Node o) {
              return this.y-o.y;
          }
      }
  
      static  int min=Integer.MAX_VALUE;
      public static void main(String[] args) throws IOException {
          FastReader sc = new FastReader();
  //(1)very very important**(never take the first problem for granted, always check the test cases) take 5 minutes more and check the edge cases
          // 5 minutes will not decreases rating as much as a wrong submission does it is easy u just think with an open mind and u will surely get the answer
          //(2)let ur brain consume the problem don't just jump to the solution. after reading the problem take a pause 1 minute
          //(3)go through the example test cases and also at least two of ur own test cases.Think of testcases which are difficult(edge cases).dry run ur concept
  
          int t = sc.nextInt();
          while (t-- > 0) {
            int n =sc.nextInt();
              int k =sc.nextInt();
            int[] a =sc.readArray(n);
  
      long max=0L;
              max=Integer.MIN_VALUE;;
      if(n-2*k-1>=0) {
          for (int i = n - 2 * k; i <= n; i++)
              for (int j = i + 1; j <= n; j++) {
                  int temp = a[i - 1]|a[j - 1];
                  max = Math.max(max, (1L*i * j - 1L*k * temp));
              }
      }
      else
      { for (int i = 1; i <= n; i++)
          for (int j = i + 1; j <= n; j++) {
              int temp = a[i - 1]|a[j - 1];
              max = Math.max(max, (1L*i * j - 1L*k * temp));
  
          }
  
      }
       System.out.println(max);
          }
  
  
  
      }
  
  
  
  // syntax of conditional operator y=(x==1)?1:0;
  //Things to check when u r getting wrong answer
  // 1-  check the flow of the code
  //2- If ur stuck read the problem once again
  //3- before submitting always check the output format of ur code
  //4- don't check standings until problem B is done
  //5- if u r thinking ur concept is correct but still u r getting wrong answer try to implement it in another way
  //6- By default, java interpret all numeral literals as 32-bit integer values.
  // If you want to explicitely specify that this is something bigger then 32-bit integer you should use suffix L for long values.    example   long a = 600851475143L
  
  //All the functions
  
  
  
      static void debug(String s)
      { System.out.println(s);
  
      }
  
      //collections.sort use merge sort instead of quick sort but arrays.sort use quicksort whose worst time complexity is O(n^2)
      static int[] sort(int[] a)
      {         ArrayList<Integer> list = new ArrayList<>();
          for(int i=0;i<a.length;i++)
              list.add(a[i]);
  
          Collections.sort(list);
          int ind=0;
          for(int x:list)
              a[ind++]=x;
          return a;
  
      }
  
      //function to print an array for debugging
      static void print(int[] a) {
          for (int i = 0; i < a.length; i++)
              System.out.print(a[i] + " ");
          System.out.println();
      }
  
      static void printc(char[] a) {
          for (int i = 0; i < a.length; i++)
              System.out.print(a[i] + " ");
          System.out.println();
      }
  
  
      //normal gcd function, always put the greater number as a and the smaller number as b
      static int gcd(int a, int b) {
          if (b == 0)
              return a;
          return gcd(b, a % b);
  
      }
  
      static int lcm(int a,int b)
      {
          return (a*b)/gcd(a,b);
      }
  
  
      //to find gcd and lcm for numbers of long data type
      static long gcdl(long a, long b) {
          if (b == 0)
              return a;
          return gcdl(b, a % b);
  
      }
  
      static long lcml(long a,long b)
      {
          return (a*b)/gcdl(a,b);
      }
  
  
      //Input Reader to read faster input
      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;
          }
  
  
          int[] readArray(int n)
          {  int[] a = new int[n];
              for(int i=0;i<n;i++)
                  a[i]=nextInt();
  
              return a;
          }
      }
  
  
  
  }
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  