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: #Fast IO Region
  import collections
  import os
  import sys
  from datetime import date
  from io import BytesIO,IOBase
  BUFSIZE=8192
  class FastIO(IOBase):
      newlines=0
      def __init__(self, file):
          self._fd = file.fileno()
          self.buffer = BytesIO()
          self.writable = "x" in file.mode or "r" not in file.mode
          self.write = self.buffer.write if self.writable else None
      def read(self):
          while True:
              b = os.read(self._fd, max(os.fstat(self._fd).st_size, BUFSIZE))
              if not b:
                  break
              ptr = self.buffer.tell()
              self.buffer.seek(0, 2), self.buffer.write(b), self.buffer.seek(ptr)
          self.newlines = 0
          return self.buffer.read()
      def readline(self):
          while self.newlines == 0:
              b = os.read(self._fd, max(os.fstat(self._fd).st_size, BUFSIZE))
              self.newlines = b.count(b"\n") + (not b)
              ptr = self.buffer.tell()
              self.buffer.seek(0, 2), self.buffer.write(b), self.buffer.seek(ptr)
          self.newlines -= 1
          return self.buffer.readline()
      def flush(self):
          if self.writable:
              os.write(self._fd, self.buffer.getvalue())
              self.buffer.truncate(0), self.buffer.seek(0)
  class IOWrapper(IOBase):
      def __init__(self, file):
          self.buffer = FastIO(file)
          self.flush = self.buffer.flush
          self.writable = self.buffer.writable
          self.write = lambda s: self.buffer.write(s.encode("ascii"))
          self.read = lambda: self.buffer.read().decode("ascii")
          self.readline = lambda: self.buffer.readline().decode("ascii")
  sys.stdin, sys.stdout = IOWrapper(sys.stdin), IOWrapper(sys.stdout)
  input = lambda: sys.stdin.readline().rstrip("\r\n")
  # Get out of main function
  def main():
      pass
  # decimal to binary
  def binary(n):
      return (bin(n).replace("0b", ""))
  # binary to decimal
  def decimal(s):
      return (int(s, 2))
  # power of a number base 2
  def pow2(n):
      p = 0
      while n > 1:
          n //= 2
          p += 1
      return (p)
  # if  number is prime in √n time
  def isPrime(n):
      if (n == 1):
          return (False)
      else:
          root = int(n ** 0.5)
          root += 1
          for i in range(2, root):
              if (n % i == 0):
                  return (False)
          return (True)
  # list to string ,no spaces
  def lts(l):
      s = ''.join(map(str, l))
      return s
  # String to list
  def stl(s):
      # for each character in string to list with no spaces -->
      l = list(s)
      # for space in string  -->
      # l=list(s.split(" "))
      return l
  # Returns list of numbers with a particular sum
  def sq(a, target, arr=[]):
      s = sum(arr)
      if (s == target):
          return arr
      if (s >= target):
          return
      for i in range(len(a)):
          n = a[i]
          remaining = a[i + 1:]
          ans = sq(remaining, target, arr + [n])
          if (ans):
              return ans
  # Sieve for prime numbers in a range
  def SieveOfEratosthenes(n):
      cnt = 0
      prime = [True for i in range(n + 1)]
      p = 2
      while (p * p <= n):
          if (prime[p] == True):
              for i in range(p * p, n + 1, p):
                  prime[i] = False
          p += 1
      for p in range(2, n + 1):
          if prime[p]:
              cnt += 1
              # print(p)
      return (cnt)
  # for positive integerse only
  def nCr(n, r):
      f = math.factorial
      return f(n) // f(r) // f(n - r)
  # 1000000007
  mod = int(1e9) + 7
  def lcm(a,b):
      return abs(a * b) // math.gcd(a, b)
  import math
  import statistics
  #import random
  from bisect import bisect_right
  #from fractions import Fraction
  #from collections import OrderedDict
  #from collections i
  # mport deque
  ########################                         mat=[[0 for i in range(n)] for j in range(m)]                      ########################
  ########################                         list.sort(key=lambda x:x[1]) for sorting a list according to second element in sublist            ########################
  ########################                         Speed: STRING < LIST < SET,DICTIONARY                      ########################
  ########################                         from collections import deque                              ########################
  ########################                         ASCII of A-Z= 65-90                                        ########################
  ########################                         ASCII of a-z= 97-122                                       ########################
  ########################                         d1.setdefault(key, []).append(value)                       ########################
  #sys.setrecursionlimit(500000)          #Gives memory limit exceeded if used a lot
  #import heapq
  for __ in range(int(input())):
      n=int(input())
      a=list(map(int,input().split()))
      ans=[]
      if(n%2==0):
          for i in range(0,n,2):
              ans.append(a[i+1])
              ans.append(-a[i])
      else:
          for i in range(0,n-3,2):
              ans.append(a[i+1])
              ans.append(-a[i])
          if(a[-1]+a[-2]!=0):
              ans.append(a[-1]+a[-2])
              ans.append(-a[-3])
              ans.append(-a[-3])
          elif(a[-2]+a[-3]!=0):
              ans.append(-a[-1])
              ans.append(-a[-1])
              ans.append(a[-2]+a[-3])
          else:
              ans.append(-a[-2])
              ans.append(a[-1]+a[-3])
              ans.append(-a[-2])
      print(*ans)
  