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.*;
  public class class44 {
  	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;
          }
      }
  	static long gcd(long a,long b)
  	{
  		if(a==0)
  		{
  			return b;
  		}
  		return gcd(b%a,a);
  	}
  	static long findgcd(long a[])
  	{
  		long result=0;
  		for(long val:a)
  		{
  			result=gcd(result,val);
  			if(result==1)
  			{
  				return 1;
  			}
  		}
  		return result;
  	}
   
   
  	public static void main(String[] args) {
  		FastReader input=new FastReader();
  		int t=input.nextInt();
  		while(t-->0) {
  			int n=input.nextInt();
  	        long a[]=new long[n];
  	        if(n%2==0) {
  	        for(int i=0;i<n;i++) {
  	        	a[i]=input.nextLong();
  	        	if(i%2!=0) {
  	  	        System.out.print(-a[i]+" ");
  	  	        System.out.print(a[i-1]+" ");
  	        	}
  	        }
  		}
  	        else {
  	        	for(int i=0;i<n-3;i++) {
  	        		a[i]=input.nextLong();
  	        		if(i%2!=0) {
  	        			 System.out.print(-a[i]+" ");
  	     	  	        System.out.print(a[i-1]+" ");
  	        		}
  	        	}
  	        	a[n-3]=input.nextLong();
  	        	a[n-2]=input.nextLong();
  	        	a[n-1]=input.nextLong();
  	        long s1=a[n-3];
  	        long s2=a[n-2];
  	        long s3=a[n-1];
  	        if(s1+s2!=0) {
  	            System.out.print(-s3+" ");
  		        System.out.print(-s3+" ");
  		        System.out.print(s1+s2+" ");
  	        }
  	        else {
  	        	if(s1+s3!=0) {
  	        	    System.out.print(-s2+" ");
  	       	        System.out.print(s1+s3+" ");
  	       	        System.out.print(-s2+" ");
  	        	}
  	        	else {
  	        		if(s2+s3!=0) {
  	        		       System.out.print(s2+s3+" ");
  	        		        System.out.print(-s1+" ");
  	        		        System.out.print(-s1+" ");
  	        		}
  	        	}
  	        }
  	        }
  			
  		}
  	}
   
  }