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.util.ArrayList;
  import java.util.Collections;
  import java.util.HashMap;
  import java.util.HashSet;
  import java.util.PriorityQueue;
  import java.util.StringTokenizer;
   
   
  import java.io.*;
   
  public class Div3 {
  	
  	private static class MyScanner {
  	    BufferedReader br;
  	    StringTokenizer st;
   
  	    public MyScanner() {
  	       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 long gcd(long a, long b)
  	{
  		if(b==0)
  			 return a;
  		
  		return gcd(b,a%b);
  		
  	}
  	
  	public static long lcm(long a, long b)
  	{
  		return (a*b)/gcd(a,b);
  	}
  	
  	public static void solution (int n, long[] arr) {
  		
  		long[] ans = new long[n];
  		for(int i = 0; i<n/2; i++)
  			ans[i] = arr[n-1-i];
  		for(int i = n/2; i<n; i++)
  			ans[i] = -1*arr[n-1-i];
  			
  		if(n%2==1)
  		{
  			if(arr[n/2-1]+arr[n/2+1]!=0)
  			{
  				ans[n/2] = -1*(arr[n/2-1]+arr[n/2+1]);
  			    ans[n/2-1] = arr[n/2];
  			    ans[n/2+1] = arr[n/2];
  			}
  			
  			if(arr[n/2-1]+arr[n/2]!=0)
  			{
  				ans[n/2+1] = -1*(arr[n/2-1]+arr[n/2]);
  			    ans[n/2-1] = arr[n/2+1];
  			    ans[n/2] = arr[n/2+1];
  			}
  			
  			if(arr[n/2]+arr[n/2+1]!=0)
  			{
  				ans[n/2-1] = -1*(arr[n/2]+arr[n/2+1]);
  			    ans[n/2] = arr[n/2-1];
  			    ans[n/2+1] = arr[n/2-1];
  			}
  		}
  		
  		for(int i = 0; i<n; i++)
  			out.print(ans[i]+" ");
  		
  		out.println();
  	}
  	
  					
  private static PrintWriter out = new PrintWriter(System.out);
   
  public static void main (String[] args)
    {
  	MyScanner s =  new MyScanner();
  	  
      int t = s.nextInt();
      
      while(t-->0)
      {
  		int n = s.nextInt();
  		long[] arr = new long[n];
  		for(int i = 0; i<n; i++)
  			arr[i] = s.nextLong();
  		
          solution(n,arr);
      }
      
      out.flush();
      out.close();
      
  }
  }