description: Vupsen and Pupsen were gifted an integer array. Since Vupsen doesn't like the number 0, he threw away all numbers equal to 0 from the array. As a result, he got an array a of length n.
  
  Pupsen, on the contrary, likes the number 0 and he got upset when he saw the array without zeroes. To cheer Pupsen up, Vupsen decided to come up with another array b of length n such that ∑_{i=1}^{n}a_i ⋅ b_i=0. Since Vupsen doesn't like number 0, the array b must not contain numbers equal to 0. Also, the numbers in that array must not be huge, so the sum of their absolute values cannot exceed 10^9. Please help Vupsen to find any such array b!
  
  Input
  
  The first line contains a single integer t (1 ≤ t ≤ 100) — the number of test cases. The next 2 ⋅ t lines contain the description of test cases. The description of each test case consists of two lines.
  
  The first line of each test case contains a single integer n (2 ≤ n ≤ 10^5) — the length of the array.
  
  The second line contains n integers a_1, a_2, …, a_n (-10^4 ≤ a_i ≤ 10^4, a_i ≠ 0) — the elements of the array a.
  
  It is guaranteed that the sum of n over all test cases does not exceed 2 ⋅ 10^5.
  
  Output
  
  For each test case print n integers b_1, b_2, …, b_n — elements of the array b (|b_1|+|b_2|+… +|b_n| ≤ 10^9, b_i ≠ 0, ∑_{i=1}^{n}a_i ⋅ b_i=0).
  
  It can be shown that the answer always exists.
  
  Example
  
  Input
  
  
  3
  2
  5 5
  5
  5 -2 10 -9 4
  7
  1 2 3 4 5 6 7
  
  
  Output
  
  
  1 -1
  -1 5 1 -1 -1
  -10 2 2 -3 5 -1 -1
  
  Note
  
  In the first test case, 5 ⋅ 1 + 5 ⋅ (-1)=5-5=0. You could also print 3 -3, for example, since 5 ⋅ 3 + 5 ⋅ (-3)=15-15=0
  
  In the second test case, 5 ⋅ (-1) + (-2) ⋅ 5 + 10 ⋅ 1 + (-9) ⋅ (-1) + 4 ⋅ (-1)=-5-10+10+9-4=0.
solution: import java.io.BufferedReader; 
  import java.io.IOException; 
  import java.io.InputStreamReader; 
  import java.util.Scanner; 
  import java.util.StringTokenizer;
  import java.util.*;
  public class codeforcesB{
   public 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; 
          } 
     } 
   public static void main(String args[]){
      FastReader sc=new FastReader();
      StringBuilder sb=new StringBuilder();
      int t=sc.nextInt();
      while(t-->0){
        int n=sc.nextInt();
        int ar[]=new int[n];
        int sum=0;
        for(int i=0;i<n;i++){ar[i]=sc.nextInt();}
        if(n%2==0){
            for(int i=0;i<n;i++){
                if(i%2==0){sb.append(-1*ar[i+1]+" ");}
                else{sb.append(ar[i-1]+" ");}
              }
             
          }
        else{
            if(ar[1]+ar[0]!=0){
            sb.append(ar[2]+" "+ar[2]+" "+-1*(ar[1]+ar[0])+" ");}
            else{
                if(ar[2]+ar[1]!=0){
                    sb.append(-1*(ar[2]+ar[1])+" "+ar[0]+" "+ar[0]+" ");
                }
                else{
                    sb.append(ar[1]+" "+-1*(ar[2]+ar[0])+" "+ar[1]+" ");
                }
            }
            for(int i=3;i<n;i++){
                if(i%2==1){sb.append(-1*ar[i+1]+" ");}
                else{sb.append(ar[i-1]+" ");}
              }
          }
        sb.append("\n");
      }
      System.out.print(sb.toString());
     }
  }