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 sys
  
  
  input = sys.stdin.readline
  
  
  def gcd(a, b):
      if b == 0:
          return a
      return gcd(b, a%b)
  
  
  def find_b(arr):
      min_abs = 10**4+1
      idx = -1
      
      for i in range(len(arr)):
          if abs(arr[i]) < abs(min_abs):
              min_abs = arr[i]
              idx = i
      
      b = [0 for _ in range(len(arr))]
      
      v = 0
      for i in range(len(arr)):
          if i == idx:
              continue
          
          g = gcd(min_abs, arr[i])
          
          t1 = -arr[i]//g
          t2 = min_abs//g
          
          if v >= 0:
              if t1 < 0:
                  v += t1
                  b[i] = t2
              else:
                  v -= t1
                  b[i] = -t2
          
          else:
              if t1 < 0:
                  v -= t1
                  b[i] = -t2
              else:
                  v += t1
                  b[i] = t2
      
      if v == 0:
          min_used = 10**4+1
          min_idx = 0
          for i in range(len(arr)):
              if i == idx:
                  continue
              if abs(b[i]) < abs(min_used):
                  min_used = b[i]
                  min_idx = i
          
          g = gcd(min_abs, arr[min_idx])
          
          t1 = -arr[min_idx]//g
          t2 = min_abs//g
          
          if min_used * t2 < 0:
              v -= t1
              b[min_idx] -= t2
          else:
              v += t1
              b[min_idx] += t2
      
      b[idx] = v
      
      for i in range(len(arr)):
          print(b[i], end=" ")
      print()
  
  
  if __name__ == "__main__":
      for _ in range(int(input())):
          n = int(input())
          arr = list(map(int, input().split()))
          find_b(arr)
  