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: /*
          "Everything in the universe is balanced. Every disappointment
                  you face in life will be balanced by something good for you!
                          Keep going, never give up."
  
  */
  
  
  import java.util.*;
  import java.lang.*;
  import java.io.*;
  
  public class Solution {
      public static void main(String[] args) throws java.lang.Exception {
          out = new PrintWriter(new BufferedOutputStream(System.out));
          sc = new FastReader();
  
          int test = sc.nextInt();
          for (int t = 0; t < test; t++) {
              solve();
          }
          out.close();
      }
  
      private static void solve() {
          int n = sc.nextInt();
          int[] arr = new int[n];
          for (int i = 0; i < n; i++) {
              arr[i] = sc.nextInt();
          }
  
          int[] res = new int[n];
          if (n % 2 == 0) {
              for (int i = 1; i < n; i += 2) {
                  res[i] = arr[i - 1];
                  res[i - 1] = -arr[i];
              }
          }else {
              for (int i = 4; i < n; i += 2) {
                  res[i] = arr[i - 1];
                  res[i - 1] = -arr[i];
              }
  
              if (arr[0] + arr[1] != 0) {
                  res[0] = -arr[2];
                  res[1] = -arr[2];
                  res[2] = arr[0] + arr[1];
              }else if (arr[0] + arr[2] != 0) {
                  res[0] = -arr[1];
                  res[2] = -arr[1];
                  res[1] = arr[0] + arr[2];
              }else {
                  res[1] = -arr[0];
                  res[2] = -arr[0];
                  res[0] = arr[1] + arr[2];
              }
          }
  
          for (int i = 0; i < n; i++) {
              out.print(res[i] + " ");
          }
          out.println();
      }
  
  
      public static FastReader sc;
      public static PrintWriter out;
      static class FastReader
      {
          BufferedReader br;
          StringTokenizer str;
  
          public FastReader()
          {
              br = new BufferedReader(new
                      InputStreamReader(System.in));
          }
  
          String next()
          {
              while (str == null || !str.hasMoreElements())
              {
                  try
                  {
                      str = new StringTokenizer(br.readLine());
                  }
                  catch (IOException  end)
                  {
                      end.printStackTrace();
                  }
              }
              return str.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 end)
              {
                  end.printStackTrace();
              }
              return str;
          }
      }
  }