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: //#Rohitpratap311
  //Keep_Calm_And_Stay_Happy
  import java.io.*;
  import java.util.*;
  public class Main {
      public static void main(String[] args) {
          FastReader input=new FastReader();
          PrintWriter out=new PrintWriter(System.out);
          int T=input.nextInt();
          while(T-->0)
          {
              int n=input.nextInt();
              int a[]=new int[n];
              for(int i=0;i<n;i++)
              {
                  a[i]=input.nextInt();
              }
              int b[]=new int[n];
              if(n%2==0)
              {
                  for(int i=0;i<n;i+=2)
                  {
                      int v1=Math.abs(a[i]),v2=Math.abs(a[i+1]);
                      int l=lcm(v1,v2);
                      int x=l/v1,y=l/v2;
                      if((a[i]>=0 && a[i+1]<0) || (a[i]<0 && a[i+1]>=0))
                      {
                          b[i]=x;
                          b[i+1]=y;
                      }
                      else
                      {
                          b[i]=x;
                          b[i+1]=-y;
                      }
                  }
                  for(int i=0;i<n;i++)
                  {
                      out.print(b[i]+" ");
                  }
                  out.println();
              }
              else
              {
                  for(int i=0;i<n-3;i+=2)
                  {
                      int v1=Math.abs(a[i]),v2=Math.abs(a[i+1]);
                      int l=lcm(v1,v2);
                      int x=l/v1,y=l/v2;
                      if((a[i]>=0 && a[i+1]<0) || (a[i]<0 && a[i+1]>=0))
                      {
                          b[i]=x;
                          b[i+1]=y;
                      }
                      else
                      {
                          b[i]=x;
                          b[i+1]=-y;
                      }
                  }
                  int l1=lcm(Math.abs(a[n-3]),Math.abs(a[n-2]));
                  int x=l1/Math.abs(a[n-3]),y=l1/Math.abs(a[n-2]);
                  int l2=lcm(Math.abs(a[n-3]),Math.abs(a[n-1]));
                  int z=l2/Math.abs(a[n-3]);
                  if((a[n-3]>=0 && a[n-2]<0) || (a[n-3]<0 && a[n-2]>=0))
                  {
  
                  }
                  else
                  {
                      y=-y;
                  }
                  x+=z;
                  int sum=a[n-3]*x+a[n-2]*y;
                  sum=-sum;
                  z=sum/a[n-1];
                  b[n-3]=x;
                  b[n-2]=y;
                  b[n-1]=z;
                  for(int i=0;i<n;i++)
                  {
                      out.print(b[i]+" ");
                  }
                  out.println();
              }
          }
          out.close();
      }
      public static int gcd(int a, int b)
      {
          if(a==0)
          {
              return b;
          }
          else
          {
              return gcd(b%a,a);
          }
      }
      public static int lcm(int a, int b)
      {
          return (a/gcd(a,b))*b;
      }
      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;
          }
      }
  }