description: You are given n integers a_1, a_2, …, a_n. Find the maximum value of max(a_l, a_{l + 1}, …, a_r) ⋅ min(a_l, a_{l + 1}, …, a_r) over all pairs (l, r) of integers for which 1 ≤ l < r ≤ n.
  
  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 a single integer n (2 ≤ n ≤ 10^5).
  
  The second line of each test case contains n integers a_1, a_2, …, a_n (1 ≤ a_i ≤ 10^6).
  
  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 the product from the statement.
  
  Example
  
  Input
  
  
  4
  3
  2 4 3
  4
  3 2 3 1
  2
  69 69
  6
  719313 273225 402638 473783 804745 323328
  
  
  Output
  
  
  12
  6
  4761
  381274500335
  
  Note
  
  Let f(l, r) = max(a_l, a_{l + 1}, …, a_r) ⋅ min(a_l, a_{l + 1}, …, a_r).
  
  In the first test case, 
  
    * f(1, 2) = max(a_1, a_2) ⋅ min(a_1, a_2) = max(2, 4) ⋅ min(2, 4) = 4 ⋅ 2 = 8. 
    * f(1, 3) = max(a_1, a_2, a_3) ⋅ min(a_1, a_2, a_3) = max(2, 4, 3) ⋅ min(2, 4, 3) = 4 ⋅ 2 = 8. 
    * f(2, 3) = max(a_2, a_3) ⋅ min(a_2, a_3) = max(4, 3) ⋅ min(4, 3) = 4 ⋅ 3 = 12. 
  
  
  
  So the maximum is f(2, 3) = 12.
  
  In the second test case, the maximum is f(1, 2) = f(1, 3) = f(2, 3) = 6.
solution: /* package codechef; // don't place package name! */
  import java.util.*;
  
  
  import java.lang.*;
  import java.io.*;
  import java.math.BigInteger;
  
  public class Main
  {           public static void main(String args[])throws java.lang.Exception
          { 
             BufferedReader br=new BufferedReader(new InputStreamReader(System.in));
             PrintWriter pt=new PrintWriter(System.out);
  		   int t=Integer.parseInt(br.readLine());
  		   long max=0l;
  		   for(int xyz=0; xyz<t;xyz++)
  		   { int n=Integer.parseInt(br.readLine());
  			int arr[]=new int[n];
  			 String str=br.readLine();
  			StringTokenizer st=new StringTokenizer(str," ");
  			for(int i=0; i<n; i++)
  			{
  				arr[i]=Integer.parseInt(st.nextToken());
  			}
  			max=Integer.MIN_VALUE;
  			
  			for( int j=0; j<n-1; j++)
  			{ 
  				if((1l*arr[j]*arr[j+1])>max)
  				{
  					max=1l*arr[j]*arr[j+1];
  				}
  			}
  			pt.println(max);	
  		}
  			
  			pt.close();
  		
  		}
  	}	