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: // Problem: D. Vupsen, Pupsen and 0
  // Contest: Codeforces - Codeforces Round #750 (Div. 2)
  // URL: https://codeforces.com/contest/1582/problem/D
  // Memory Limit: 256 MB
  // Time Limit: 1000 ms
  
  
  import java.io.*;
  import java.util.*;
   
  public class Solution
  {
  	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());
          }
   
          String nextLine()
          {
              String str = "";
              try {
                  str = br.readLine();
              }
              catch (IOException e) {
                  e.printStackTrace();
              }
              return str;
          }
      }
      
      static long gcd(long a, long b)
      {
          if (a == 0)
              return b;
          return gcd(b % a, a);
      }
       
      // method to return LCM of two numbers
      static long lcm(long a, long b)
      {
          return (a / gcd(a, b)) * b;
      }
      static void swap(long arr[], int i, int j){
      	long temp = arr[i];
      	arr[i] = arr[j];
      	arr[j] = temp;
      }
      
      static long[] getRes(long arr[], int n){
      	long[] res = new long[n];
      	int start = 0;
      	if (n%2==1){
      		int op = 1;
      		start = 3;
      		long a = arr[0]+arr[1];
      		
      		long b = arr[2];
      		if (a==0){
      			op = 2;
      			a = arr[0]+arr[2];
      			b = arr[1];
      			if (a==0){
      				op = 3;
      				a = arr[1]+arr[2];
      				b = arr[0];
      			}
      		}
      		int neg = 0;
      		if (a<0&&b<0){
      			neg = 2;
      			a = -a;
      			b = -b;
      		}
      		else if (a<0||b<0){
      			neg=1;
      			if (a<0){
      				a = -a;
      			}
      			else {
      				b = -b;
      			}
      		}
      		
      		long lc = lcm(a,b);
      		if (neg%2==0){
      			long mulb = -lc/b;
      			long mula = lc/a;
      			res[0] = mula;
      			res[1] = mula;
      			res[2] = mulb;
      		}
      		else {
      			long mulb = lc/b;
      			long mula = lc/a;
      			res[0] = mula;
      			res[1] = mula;
      			res[2] = mulb;
      		}
      		if (op==2){
      			swap(res,2,1);
      		}
      		else if (op==3){
      			// System.out.println("In 3");
      			swap(res,0,2);
      		}
      	}
      	
      	for (int i = start; i<n; i+=2){
      		long a = arr[i];
      		long b= arr[i+1];
      		int neg = 0;
      		if (a<0&&b<0){
      			neg = 2;
      			a = -a;
      			b = -b;
      		}
      		else if (a<0||b<0){
      			neg=1;
      			if (a<0){
      				a = -a;
      			}
      			else {
      				b = -b;
      			}
      		}
      		
      		long lc = lcm(a,b);
      		if (neg%2==0){
      			long mulb = -lc/b;
      			long mula = lc/a;
      			res[i] = mula;
      			res[i+1] = mulb;
      		}
      		else {
      			long mulb = lc/b;
      			long mula = lc/a;
      			res[i] = mula;
      			res[i+1] = mulb;
      		}
      	}
      	return res;
      	
      }
      
      public static void main(String args[]){
          FastReader s = new FastReader();
          int t = s.nextInt();
          while(t-->0){
          	int n = s.nextInt();
          	long arr[] = new long[n];
          	for (int i = 0; i<n; i++){
          		arr[i] = s.nextLong();
          	}
          	long res[] = getRes(arr,n);
          	for (long ele: res){
          		System.out.print(ele+" ");
          	}
          	System.out.println();
          }
      }
  }
  