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: import java.io.*;
  import java.util.ArrayList;
  import java.util.Arrays;
  import java.util.StringTokenizer;
  import java.util.List;
   import java.util.*;
   public class realfast implements Runnable 
    {
      private static final int INF = (int) 1e9;
      long in= 1000000007;
      long fac[]= new long[1000001];
      long inv[]=new long[1000001];
      public  void solve() throws IOException 
      {
  
          
           int t = readInt();
  
          for(int f =0;f<t;f++)
          {
               int n = readInt();
               long arr[]=new long[n];
               for(int i =0;i<n;i++)
                  arr[i]= readInt();
               long max = arr[0]*arr[1];
               for(int i=1;i<n-1;i++)
               {
                  max=Math.max(max,arr[i]*arr[i+1]);
               }
               out.println(max);
          }
  
          
  
  
  
      }
      
      public int value (int seg[], int left , int right ,int index, int l, int r)
      {
              
              if(left>right)
              {
                return -100000000;
              }
              if(right<l||left>r)
                  return -100000000;
              if(left>=l&&right<=r)
                  return seg[index];
              int mid = left+(right-left)/2;
              int val = value(seg,left,mid,2*index+1,l,r);
              int val2 = value(seg,mid+1,right,2*index+2,l,r);
              return Math.max(val,val2);
  
      }
     
      public int gcd(int a , int b )
      {
        if(a<b)
        {
          int t =a;
          a=b;
          b=t;
        }
        if(a%b==0)
          return b ;
        return gcd(b,a%b);
      }
      public long pow(long n , long p,long m)
      {
           if(p==0)
              return 1;
          long val = pow(n,p/2,m);;
          val= (val*val)%m;
          if(p%2==0)
              return val;
          else
              return (val*n)%m;
      }
      
      
      ///////////////////////////////////////////////////////////////////////////////////////////////////////////////////
      public static void main(String[] args) {
          new Thread(null, new realfast(), "", 128 * (1L << 20)).start();
      }
   
      private static final boolean ONLINE_JUDGE = System.getProperty("ONLINE_JUDGE") != null;
      private BufferedReader reader;
      private StringTokenizer tokenizer;
      private PrintWriter out;
   
      @Override
      public void run() {
          try {
              if (ONLINE_JUDGE || !new File("input.txt").exists()) {
                  reader = new BufferedReader(new InputStreamReader(System.in));
                  out = new PrintWriter(System.out);
              } else {
                  reader = new BufferedReader(new FileReader("input.txt"));
                  out = new PrintWriter("output.txt");
              }
              solve();
          } catch (IOException e) {
              throw new RuntimeException(e);
          } finally {
              try {
                  reader.close();
              } catch (IOException e) {
                  // nothing
              }
              out.close();
          }
      }
   
      private String readString() throws IOException {
          while (tokenizer == null || !tokenizer.hasMoreTokens()) {
              tokenizer = new StringTokenizer(reader.readLine());
          }
          return tokenizer.nextToken();
      }
   
      @SuppressWarnings("unused")
      private int readInt() throws IOException {
          return Integer.parseInt(readString());
      }
   
      @SuppressWarnings("unused")
      private long readLong() throws IOException {
          return Long.parseLong(readString());
      }
   
      @SuppressWarnings("unused")
      private double readDouble() throws IOException {
          return Double.parseDouble(readString());
      }
  }
  class edge implements Comparable<edge>{
      int u ;
      int v;
      
      edge(int  u, int v)
      {
         this.u=u;
         this.v=v;
      }
      public int compareTo(edge e)
      {
          return this.v-e.v;
      }
  }