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: #!/usr/bin/env python3
  # from typing import *
  
  import sys
  import io
  import math
  import collections
  import decimal
  import itertools
  import bisect
  import heapq
  
  
  def input():
      return sys.stdin.readline()[:-1]
  
  
  # sys.setrecursionlimit(1000000)
  
  # _INPUT = """1
  # 3
  # -2 2 2
  # """
  # sys.stdin = io.StringIO(_INPUT)
  
  INF = 10**10
  
  def solve(N, A):
      A1 = [(abs(A[i]), A[i], i) for i in range(N)]
      A1.sort(reverse=True)
      result = [0] * N
      j = 0
      while j < N-3:
          ab1, a1, i1 = A1[j]
          ab2, a2, i2 = A1[j+1]
          result[i1] = a2
          result[i2] = -a1
          j += 2
  
      if N % 2 == 0:
          ab1, a1, i1 = A1[j]
          ab2, a2, i2 = A1[j+1]
          result[i1] = a2
          result[i2] = -a1
      else:
          for k1, k2, k3 in itertools.permutations([j, j+1, j+2]):
              ab1, a1, i1 = A1[k1]
              ab2, a2, i2 = A1[k2]
              ab3, a3, i3 = A1[k3]
              if a2 + a3 != 0:
                  result[i1] = a2+a3
                  result[i2] = -a1
                  result[i3] = -a1
                  break
  
      return result
  
  T0 = int(input())
  for _ in range(T0):
      N = int(input())
      A = list(map(int, input().split()))
      print(*solve(N, A))
      