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,os,io
  input = sys.stdin.readline # for strings
  # input = io.BytesIO(os.read(0, os.fstat(0).st_size)).readline # for non-strings
  
  PI = 3.141592653589793238460
  INF =  float('inf')
  MOD  = 1000000007
  # MOD = 998244353
  
  
  def bin32(num):
  	return '{0:032b}'.format(num)
  
  def add(x,y):
  	return (x+y)%MOD
  
  def sub(x,y):
  	return (x-y+MOD)%MOD
  
  def mul(x,y):
  	return (x*y)%MOD
  
  def gcd(x,y):
  	if y == 0:
  		return x
  	return gcd(y,x%y)
  
  def lcm(x,y):
  	return (x*y)//gcd(x,y)
  
  def power(x,y):
  	res = 1
  	x%=MOD
  	while y!=0:
  		if y&1 :
  			res = mul(res,x)
  		y>>=1
  		x = mul(x,x)
  		
  	return res
  		
  def mod_inv(n):
  	return power(n,MOD-2)
  
  def prob(p,q):
  	return mul(p,power(q,MOD-2))    
    
  def ii():
  	return int(input())
  
  def li():
  	return [int(i) for i in input().split()]
  
  def ls():
  	return [i for i in input().split()]
  
  for t in range(ii()):
  	t+=1
  	n = ii()
  	a = li()
  	b = [0 for i in range(n)]
  	if n % 2 == 0:
  		l = 0
  		r = n-1
  		while l < r:
  			g = gcd(abs(a[l]) , abs(a[r]))
  
  			x = a[l]//g
  			y = a[r]//g
  			b[l] = -y
  			b[r] = x
  		
  			l+=1
  			r-=1
  		c = [a[i]*b[i] for i in range(n)]
  		print(*b)
  	else:
  		x = 0
  		y = -1
  
  		for i in range(1 , n):
  			if a[i] + a[x] != 0 and i != x:
  				y = i
  				break
  		if y == -1:
  			x = 1
  			for i in range( n):
  				if a[i] + a[x] != 0 and i != x:
  					y = i
  					break
  		z = -1
  		for i in range(n):
  			if i != x and i != y:
  				xx = a[x] + a[y]
  				yy = a[i]
  
  				g = gcd(abs(xx) , abs(yy))
  				xx//=g
  				yy//=g
  				# print(x ,y , i, xx , yy)
  				b[i] = -xx
  				b[x] = yy
  				b[y] = yy
  				break
  		l = 0
  		r = n-1
  		# print(x , y)
  		# print(*b)
  		while l < r:
  			if b[l]!=0:
  				l+=1
  				continue
  			if b[r] != 0:
  				r-=1
  				continue
  			
  			g = gcd(abs(a[l]) , abs(a[r]))
  
  			x = a[l]//g
  			y = a[r]//g
  			b[l] = -y
  			b[r] = x
  		
  			l+=1
  			r-=1
  		c = [a[i]*b[i] for i in range(n)]
  		print(*b)
  
  