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: # This code is contributed by Siddharth
  
  
  from sys import *
  input = stdin.readline
  
  
  
  import threading
  from bisect import *
  import math
  from collections import *
  import operator
  from heapq import *
  from itertools import *
  inf=10**19
  mod=10**9+7
  MOD=998244353
  S1 = 'abcdefghijklmnopqrstuvwxyz'
  S2 = 'ABCDEFGHIJKLMNOPQRSTUVWXYZ'
  dx = [-1,0]
  dy = [0,-1]
  # inverse modulo power pow(a,-1,mod) - it only works on py 3.8 ( *not in pypy )
  setrecursionlimit(200005)
  def asc(c):
      return ord(c)-97+1
  
  
  
  
  
  # ==========================================> Code Starts Here <=====================================================================)
  
  def gcd(a, b):
      if b == 0:
          return a
      else:
          return gcd(b, a % b)
  
  
  def lcm(a, b):
      a=abs(a)
      b=abs(b)
      return (a * b) // gcd(a, b)
  
  
  
  for _ in range(int(input())):
      n=int(input())
      a=list(map(int,input().split()))
      # a.sort()
      temp=[0]*n
      if n%2==0:
          for i in range(0,n,2):
              gg=lcm(a[i],a[i+1])
              temp[i]=(-gg//a[i])
              temp[i+1]=(gg//a[i+1])
      else:
          for i in range(0,n-3,2):
              gg=lcm(a[i],a[i+1])
              temp[i]=(-gg//a[i])
              temp[i+1]=(gg//a[i+1])
          gg=lcm(a[-1],a[-2])
          gg=lcm(gg,a[-3])
  
          temp[-3]=(-gg//a[-3])
          temp[-2]=(-gg // a[-2])
          temp[-1]=((gg * 2) // a[-1])
      print(*temp)
  
  
  
  
  
  
  