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: from sys import stdin, stdout
  from random import randint
  print = stdout.write
  input = stdin.readline
  
  
  def gcd(a, b):
      while b:
          a, b = b, a % b
      return a
  
  def lcm(a, b):
      return a * b // gcd(a, b)
  
  def solve_test():
      n = int(input())
      a = [int(x) for x in input().split()]
      A = a.copy()
      ans = []
      final = []
      if n%2 == 1:
          T = 1
          if a[-2] // abs(a[-2]) != a[-3] // abs(a[-3]):
              a[-3] = -a[-3]
              T = -1
          d = lcm(a[-1], a[-2]+a[-3])
          k = d//(a[-2]+a[-3])
          final.append(-k*T)
          final.append(-k)
          final.append(d//a[-1])
          a.pop()
          a.pop()
          a.pop()
          n -= 3
  
      for i in range(n//2):
          d = lcm(a[i*2], a[i*2+1])
          ans.append(-d//a[i*2])
          ans.append(d//a[i*2+1])
      ans += final
      # assert sum(ans[i] * A[i] for i in range(n)) == 0
      return " ".join(str(s) for s in ans)
  
  def main(args=None):
      tests = int(input())
      for _ in range(tests):
          print(f"{solve_test()}\n")
  
  if __name__ == '__main__':
      main()