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.OutputStream;
  import java.io.IOException;
  import java.io.InputStream;
  import java.io.OutputStream;
  import java.io.PrintWriter;
  import java.io.IOException;
  import java.io.InputStreamReader;
  import java.io.FileNotFoundException;
  import java.util.StringTokenizer;
  import java.io.Writer;
  import java.io.BufferedReader;
  import java.io.InputStream;
  
  /**
   * Built using CHelper plug-in
   * Actual solution is at the top
   *
   * @author Asgar Javadov
   */
  public class Main {
      public static void main(String[] args) {
          InputStream inputStream = System.in;
          OutputStream outputStream = System.out;
          InputReader in = new InputReader(inputStream);
          OutputWriter out = new OutputWriter(outputStream);
          DVupsenPupsenAnd0 solver = new DVupsenPupsenAnd0();
          int testCount = Integer.parseInt(in.next());
          for (int i = 1; i <= testCount; i++)
              solver.solve(i, in, out);
          out.close();
      }
  
      static class DVupsenPupsenAnd0 {
          public void solve(int testNumber, InputReader in, OutputWriter out) {
              int n = in.nextInt();
              var a = in.readIntArray(n);
  
              var b = new int[n];
              if (n % 2 == 0) {
                  for (int i = 0; i < n; i += 2) {
                      b[i] = -a[i + 1];
                      b[i + 1] = a[i];
                  }
                  out.println(b);
                  return;
              }
  
              for (int i = 0; i + 1 < n - 1; i += 2) {
                  b[i] = -a[i + 1];
                  b[i + 1] = a[i];
              }
              b[n - 2] -= a[n - 1];
              b[n - 1] = a[n - 2];
  
              if (b[n - 2] == 0) {
                  b[n - 2] -= a[n - 1];
                  b[n - 1] += a[n - 2];
              }
  
              out.println(b);
  
          }
  
      }
  
      static class OutputWriter extends PrintWriter {
          public OutputWriter(OutputStream outputStream) {
              super(outputStream);
          }
  
          public OutputWriter(Writer writer) {
              super(writer);
          }
  
          public OutputWriter(String filename) throws FileNotFoundException {
              super(filename);
          }
  
          public void println(int[] array) {
              for (int i = 0; i < array.length; i++) {
                  if (i > 0) print(' ');
                  print(array[i]);
              }
              println();
          }
  
          public void close() {
              super.close();
          }
  
      }
  
      static class InputReader extends BufferedReader {
          StringTokenizer tokenizer;
  
          public InputReader(InputStream inputStream) {
              super(new InputStreamReader(inputStream), 32768);
          }
  
          public InputReader(String filename) {
              super(new InputStreamReader(Thread.currentThread().getContextClassLoader().getResourceAsStream(filename)));
          }
  
          public String next() {
              while (tokenizer == null || !tokenizer.hasMoreTokens()) {
                  try {
                      String line = readLine();
                      if (line == null) continue;
                      tokenizer = new StringTokenizer(line);
                  } catch (IOException e) {
                      throw new RuntimeException();
                  }
              }
              return tokenizer.nextToken();
          }
  
          public Integer nextInt() {
              return Integer.valueOf(next());
          }
  
          public int[] readIntArray(int size) {
              int[] array = new int[size];
              for (int i = 0; i < size; i++)
                  array[i] = nextInt();
  //        IntStream.generate(this::nextInt).limit(size).toArray();
              return array;
          }
  
      }
  }
  
  