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: /*
                         _oo0oo_
                        o8888888o
                        88" . "88
                        (| -_- |)
                        0\  =  /0
                      ___/`---'\___
                    .' \\|     |// '.
                   / \\|||  :  |||// \
                  / _||||| -:- |||||- \
                 |   | \\\  -  /// |   |
                 | \_|  ''\---/''  |_/ |
                 \  .-\__  '-'  ___/-. /
               ___'. .'  /--.--\  `. .'___
            ."" '<  `.___\_<|>_/___.' >' "".
           | | :  `- \`.;`\ _ /`;.`/ - ` : | |
           \  \ `_.   \_ __\ /__ _/   .-` /  /
       =====`-.____`.___ \_____/___.-`___.-'=====
                         `=---='
   
  */
  
  import java.util.*;
  import java.math.*;
  import java.io.*;
  import java.lang.Math.*;
  
  public class KickStart2020 {
  	 static class FastReader {
  		BufferedReader br;
  		StringTokenizer st;
  
  		public FastReader() {
  			br = new BufferedReader(new InputStreamReader(System.in));
  		}
  
  		String next() {
  			while (st == null || !st.hasMoreElements()) {
  				try {
  					st = new StringTokenizer(br.readLine());
  				} catch (IOException e) {
  					e.printStackTrace();
  				}
  			}
  			return st.nextToken();
  		}
  
  		int nextInt() {
  			return Integer.parseInt(next());
  		}
  
  		long nextLong() {
  			return Long.parseLong(next());
  		}
  
  		double nextDouble() {
  			return Double.parseDouble(next());
  		}
  
  		float nextFloat() {
  			return Float.parseFloat(next());
  		}
  
  		String nextLine() {
  			String str = "";
  			try {
  				str = br.readLine();
  			} catch (IOException e) {
  				e.printStackTrace();
  			}
  			return str;
  		}
  	}
  
  	static long gcd(long a, long b) {
  		if (b == 0)
  			return a;
  		return gcd(b, a % b);
  
  	}
  
  	static long lcm(long a, long b) {
  		return a / gcd(a, b) * b;
  	}
  
  	public static class Pair implements Comparable<Pair> {
  		public long index;
  		public int z;
  		public int[] value;
  
  		public Pair(long index, int z, int value[]) {
  			this.index = index;
  			this.z = z;
  			this.value = value;
  		}
  
  		@Override
  		public int compareTo(Pair other) {
  			// multiplied to -1 as the author need descending sort order
  			if(other.index < this.index) return 1;
  			if(other.index > this.index) return -1;
  			else return 0;
  		}
  		@Override
  		public String toString() {
  			return this.index + " " + this.value;
  		}
  	}
  	static boolean isPrime(long d) {
  		if (d == 1)
  			return false;
  		for (int i = 2; i <= (long) Math.sqrt(d); i++) {
  			if (d % i == 0)
  				return false;
  		}
  		return true;
  	}
  	static void decimalTob(int n, int k, Stack<Integer> ss) {
            int x = n % k;
            int y = n / k;
            ss.push(x);
            if(y > 0) {
          	   decimalTob(y, k, ss);
            }
  	}
  	static long powermod(long x, long y, long mod) {
  		long ans = 1;
  		x = x % mod;
  		if (x == 0)
  			return 0;
  		int i = 1;
  		while (y > 0) {
  			if ((y & 1) != 0)
  				ans = (ans * x) % mod;
  			y = y >> 1;
  			x = (x * x) % mod;
  		}
  		return ans;
  	}
  	public static void main(String[] args) throws Exception {
  		FastReader sc = new FastReader();
  		PrintWriter out = new PrintWriter(System.out);
  		int t = sc.nextInt();
  		outerloop:
  			while(t-- > 0) {
                 int n = sc.nextInt();
                 long arr[] = new long[n];
                for(int i = 0; i < n; i++) {
              	  arr[i] = sc.nextInt();
                }
                if(n % 2 == 1) {
              	  for(int i = 0; i < n - 3; i++) {
              		  out.print(-arr[i + 1] + " ");
              		  out.print(arr[i] + " ");
              		  i++;
              	  }
              	  n--;
              	  if(arr[n - 2] + arr[n - 1] != 0) {
              		  out.print(arr[n] + " ");
              		  out.print(arr[n] + " ");
              		  out.print(-(arr[n- 1] + arr[n - 2]) + " ");
              	  }
              	  else if(arr[n - 1] + arr[n] != 0) {
              		  out.print(-(arr[n] + arr[n - 1]) + " ");
              		  out.print(arr[n - 2] + " ");
              		  out.print(arr[n - 2] + " ");
              	  }
              	  else {
              		  out.print(arr[n - 1] + " ");
              		  out.print(-(arr[n - 2] + arr[n]) + " ");
              		  out.print(arr[n - 1] + " ");
              	  }
                }
                else {
              	  for(int i = 0; i < n ; i++) {
              		  out.print(-arr[i + 1] + " ");
              		  out.print(arr[i] + " ");
              		  i++;
              	  }  
                }
                out.println();
  			}
  		out.close();
  	}
  }