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: //package codeforces;
  import java.io.BufferedReader;
  import java.io.IOException;
  import java.io.InputStreamReader;
  import java.io.PrintWriter;
  import java.util.*;
  public class solution{ 
  	public static void main(String[] args){
  		Scanner s=new Scanner(System.in);
      	PrintWriter out=new PrintWriter(System.out);
      	int t=s.nextInt();
      	for(int tt=0;tt<t;tt++) {
      		int n=s.nextInt();
      		long a[]=new long[n];
      		for(int i=0;i<n;i++) {
      			a[i]=s.nextLong();
      		}
      		if(n%2==0) {
      			for(int i=0;i<n/2;i++) {
      				out.print(-a[n-i-1]+" ");
      			}
      			for(int i=n/2;i<n;i++) {
      				out.print(a[n-i-1]+" ");
      			}
      			out.println();
      		}else {
      			for(int i=0;i<n/2-1;i++) {
      				out.print(-a[n-i-1]+" ");
      			}
      			long sum=a[n/2-1]+a[n/2+1];
      			long f=a[n/2];
      			if(sum!=0) {
      				out.print(a[n/2]+" "+(-sum)+" "+(a[n/2])+" ");
      			}else {
      				sum=a[n/2-1]+a[n/2];
      				f=a[n/2+1];
      				if(sum!=0)
      				out.print(f+" "+(f)+" "+(-sum)+" ");
      				else {
      					sum=a[n/2]+a[n/2+1];
      					f=a[n/2-1];
      					out.print((-sum)+" "+(f)+" "+(f)+" ");
      				}
      			}
      			
      			for(int i=n/2+2;i<n;i++) {
      				out.print(a[n-i-1]+" ");
      			}
      			out.println();
      		}
      	}
      	s.close();
      	out.close();
      }
  	static boolean ispal(String a) {
  		for(int i=0;i<a.length()/2;i++) {
  			if(a.charAt(i)!=a.charAt(a.length()-i-1)) {
  				return false;
  			}
  		}
  		return true;
  	}
  	static long power(long x, long y, long p)
  	  {
  	    long res = 1; 
  	    x = x % p; 
  	    if (x == 0)
  	      return 0; 
  	    while (y > 0){
  	      if ((y & 1) != 0)
  	        res = (res * x) % p;
  	      x = (x * x) % p;
  	    }
  	    return res;
  	  }
  	public static void printb(boolean ans) {
  		if(ans) {
  			System.out.println("Yes");
  		}else {
  			System.out.println("No");
  		}
  	}
  	static boolean isPrime(int n){
          if (n <= 1)
              return false;
          else if (n == 2)
              return true;
          else if (n % 2 == 0)
              return false;
          for (int i = 3; i <= Math.sqrt(n); i += 2){
              if (n % i == 0)
                  return false;
          }
          return true;
      }
  	static long lcm(long a, long b){
  	      return (a*b)/(gcd(a,b));
  	    }
  	static long gcd(long a, long b){
  	      if (b == 0)
  	        return a;
  	      return gcd(b, a % b);
  	    }
      static void sort(long [] a) {
  		ArrayList<Long> l=new ArrayList<>();
  		for (long i:a) l.add(i);
  		Collections.sort(l);
  		for (int i=0; i<a.length; i++) a[i]=l.get(i);
  	}
      static void sort(int [] a) {
  		ArrayList<Integer> l=new ArrayList<>();
  		for (int i:a) l.add(i);
  		Collections.sort(l);
  		for (int i=0; i<a.length; i++) a[i]=l.get(i);
  	}
      static class FastScanner {
  		BufferedReader br=new BufferedReader(new InputStreamReader(System.in));
  		StringTokenizer st=new StringTokenizer("");
  		String next() {
  			while (!st.hasMoreTokens())
  				try {
  					st=new StringTokenizer(br.readLine());
  				} catch (IOException e) {
  					e.printStackTrace();
  				}
  			return st.nextToken();
  		}
  		double nextDouble() {
  			return Double.parseDouble(next());
  		}
  		int nextInt() {
  			return Integer.parseInt(next());
  		}
  		boolean nextBoolean() {
  			return Boolean.parseBoolean(next());
  		}
  		int[] readArray(int n) {
  			int[] a=new int[n];
  			for (int i=0; i<n; i++) a[i]=nextInt();
  			return a;
  		}
  		long nextLong() {
  			return Long.parseLong(next());
  		}
  		long[] readLongArray(int n) {
  			long[] a=new long[n];
  			for (int i=0; i<n; i++) a[i]=nextLong();
  			return a;
  		}
  	}
      static class Pair implements Comparable<Pair>{
      	int a,b ; 
      	Pair(int a,int b){
      		this.a=a;
      		this.b=b;
      	}
      	public int compareTo(Pair o) {
      		return a-o.a;
      	}
      }
  }
  