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.*;
  import java.util.*;
  public class HelloWorld  {
  
      public static long find1(int n,int arr[],long k)
      {
  			long ans = Long.MIN_VALUE;
  	
  			for(long i=n-2;i>=Math.max(0,n-2*k-1);i--)
  			{
  				for(long j=i+1;j<n;j++)
  				{
  					long t1 = (i+1)*(j+1) - k*(arr[(int)i]|arr[(int)j]);
  					
  					//System.out.println(t1);
  					ans = Math.max(ans,t1);
  				}				
  			}
  			return ans;
  	
      }
      public static void main(String[] args) throws IOException{
  
          Reader sc=new Reader();
          PrintWriter out = new PrintWriter(System.out);
          int t=sc.nextInt();
  
          while(t-->0)
          {
  
  					int n = sc.nextInt();
  					int k = sc.nextInt();
  					int arr[]=new int[n];
  					for(int i=0;i<n;i++) arr[i]=sc.nextInt();
  					System.out.println(find1(n,arr,k));
          }
          out.flush();
      }
  
      public static long power(long x,long power)
      {
          if(power==0) return 1;
  
          long ans1 = power(x,power/2);
          ans1=ans1*ans1;
  
          if(power%2==0) return ans1;
          return x*ans1;
      }
  
      //    (a*a_inverse) = 1(mod m)
  //    finding a_inverse
      public static long modInverse(long a,long m)
      {
  //        works only when m is prime
          long g=gcd(a,m);
          if(g==1) return power(a,m-2,m);
          else return -1;
      }
  
      //    (x^power)mod(m)
      public static long power(long x,long power,long m)
      {
          if(power==0) return 1;
  
          long p = power(x,power/2,m)%m;
          p = (p*p)%m;
  
          if(power%2==0) return p;
          return (x*p)%m;
      }
      public static long gcd(long small,long large)
      {
          if(small==0) return large;
          return gcd(large % small,small);
      }
  
      public static boolean isprime(long no)
      {
          if(no<=1) return false;
          if(no<=3) return true;
          if(no%2==0 || no%3==0) return false;
          // 6k+1 6k+5 can be prime
          for(long i=5;i*i<=no;i+=6)
          {
              if(no%(i)==0 || no%(i+2)==0)
                  return false;
          }
          return true;
      }
  
      //    prime no smaller than or equal to n
      public static boolean[] prime_nos_till_no(int no)
      {
          boolean prime[]=new boolean[no+1];
  //        prime[i]== true means prime
  //        prime[i]== false means not a prime
  //        initialize prime array as true
  
          Arrays.fill(prime,true);
          prime[0]=false;
          for(int i=2;i*i<=no;i++)
          {
              if(prime[i]==true)
              {
                  for(int j=i*i;j<=no;j+=i)
                  {
                      prime[j]=false;
                  }
              }
          }
          return prime;
  
      }
      public static void shufflearray(long arr[])
      {
  
  
          int n=arr.length;
          Random rand=new Random();
          for(int i=0;i<n;i++)
          {
              long temp=arr[i];
              int randomPos=i+rand.nextInt(n-i);
              arr[i]=arr[randomPos];
              arr[randomPos]=temp;
          }
      }
      //       Arrays.sort(arr, new Comparator<pair>() {
  //        //@Override
  //        public int compare(pair o1, pair o2) {
  //            long l1=o1.a-o2.a;
  //            if(l1<0L) return -1;
  //            if(l1==0) return 0;
  //            return 1;
  //        }
  //    });
      static class Reader {
          final private int BUFFER_SIZE = 1 << 16;
          private DataInputStream din;
          private byte[] buffer;
          private int bufferPointer, bytesRead;
  
          public Reader() {
              din = new DataInputStream(System.in);
              buffer = new byte[BUFFER_SIZE];
              bufferPointer = bytesRead = 0;
          }
  
          public Reader(String file_name) throws IOException {
              din = new DataInputStream(new FileInputStream(file_name));
              buffer = new byte[BUFFER_SIZE];
              bufferPointer = bytesRead = 0;
          }
  
          public String nextLine() throws IOException {
              byte[] buf = new byte[64]; // line length
              int cnt = 0, c;
              while ((c = read()) != -1) {
                  if (c == '\n')
                      break;
                  buf[cnt++] = (byte) c;
              }
              return new String(buf, 0, cnt);
          }
          public boolean isSpaceChar(int c) {
              return c == ' ' || c == '\n' || c == '\r' || c == '\t' || c == -1;
          }
  
          public String next() throws IOException{
              int c = read();
              while (isSpaceChar(c)) c = read();
              StringBuilder res = new StringBuilder();
              do {
                  res.appendCodePoint(c);
                  c = read();
              } while (!isSpaceChar(c));
              return res.toString();
          }
  
  
          public int nextInt() throws IOException {
              int ret = 0;
              byte c = read();
              while (c <= ' ')
                  c = read();
              boolean neg = (c == '-');
              if (neg)
                  c = read();
              do {
                  ret = ret * 10 + c - '0';
              } while ((c = read()) >= '0' && c <= '9');
  
              if (neg)
                  return -ret;
              return ret;
          }
  
          public long nextLong() throws IOException {
              long ret = 0;
              byte c = read();
              while (c <= ' ')
                  c = read();
              boolean neg = (c == '-');
              if (neg)
                  c = read();
              do {
                  ret = ret * 10 + c - '0';
              }
              while ((c = read()) >= '0' && c <= '9');
              if (neg)
                  return -ret;
              return ret;
          }
  
          public double nextDouble() throws IOException {
              double ret = 0, div = 1;
              byte c = read();
              while (c <= ' ')
                  c = read();
              boolean neg = (c == '-');
              if (neg)
                  c = read();
  
              do {
                  ret = ret * 10 + c - '0';
              }
              while ((c = read()) >= '0' && c <= '9');
  
              if (c == '.') {
                  while ((c = read()) >= '0' && c <= '9') {
                      ret += (c - '0') / (div *= 10);
                  }
              }
  
              if (neg)
                  return -ret;
              return ret;
          }
  
          private void fillBuffer() throws IOException {
              bytesRead = din.read(buffer, bufferPointer = 0, BUFFER_SIZE);
              if (bytesRead == -1)
                  buffer[0] = -1;
          }
  
          private byte read() throws IOException {
              if (bufferPointer == bytesRead)
                  fillBuffer();
              return buffer[bufferPointer++];
          }
  
          public void close() throws IOException {
              if (din == null)
                  return;
              din.close();
          }
  
      }
  
  }