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
  def get_ints(): return map(int, sys.stdin.readline().strip().split())
  def get_list(): return list(map(int, sys.stdin.readline().strip().split()))
  def get_string(): return sys.stdin.readline().strip()
  def get_int(): return int(sys.stdin.readline().strip())
  def get_list_strings(): return list(map(str, sys.stdin.readline().strip().split()))
  
  
  # Output for list
  # sys.stdout.write(" ".join(map(str, final)) + "\n")
  
  # Output for int or str
  # sys.stdout.write(str(best) + "\n")
  
  
  
  def solve(n, arr):
    ans = [1 for i in range(n)]
    if n%2 == 0:
      for i in range(0,n,2):
        ans[i] = arr[i+1]
        ans[i+1] = -arr[i]
      
      print(*ans)
      return
    
    for i in range(0, n-4, 2):
      ans[i] = arr[i+1]
      ans[i+1] = -arr[i]
    
    flag = 0
  
    if (arr[n-3] != arr[n-2] and arr[n-2] != arr[n-1]) and arr[n-3] != arr[n-1]:
      ans[n-3] = arr[n-2] - arr[n-1]
      ans[n-2] = arr[n-1] - arr[n-3]
      ans[n-1] = arr[n-3] - arr[n-2]
      print(*ans)
      return
    
    if arr[n-3] + arr[n-2] != 0:
      ans[n-3] = -arr[n-1]
      ans[n-2] = -arr[n-1]
      ans[n-1] = arr[n-2] + arr[n-3]
    elif arr[n-2] + arr[n-1] != 0:
      ans[n-3] = arr[n-1] + arr[n-2]
      ans[n-2] = -arr[n-3]
      ans[n-1] = -arr[n-3]
    else:
      ans[n-3] = -arr[n-2]
      ans[n-2] = arr[n-3] + arr[n-1]
      ans[n-1] = -arr[n-2]
  
    print(*ans)
  
    
  
  
  
  
  
  
  
  
  
  T = get_int()
  while T:
    n = get_int()
    arr = get_list()
    solve(n, arr)
    T -= 1