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 java.util.*;
  import java.io.*;
  public class Main {
  		static long mod = 1000000007;
  		static long max ;
  		static PrintWriter out = new PrintWriter(new BufferedOutputStream(System.out));
  		public static void main(String[] args) throws IOException  {
  			FastReader sc = new FastReader();
  			int t = sc.nextInt();
  			while( t-- > 0) {
  				int n = sc.nextInt();
  //				ArrayList<Long> x = new ArrayList<>();
  				long arr[] = new long[n];
  				for( int i =0 ; i< n;i++) {
  					arr[i] = sc.nextLong();
  				}
  				if( n %2 == 0) {
  					for( int i = 0 ;i < n-1 ; i+=2) {
  						long l = lcm(arr[i], arr[i+1]);
  						out.print(l/arr[i] + " " + -1*l/arr[i+1] + " ");
  //						x.add( l/arr[i] );
  //						x.add( -1*l/arr[i+1]);
  					}
  				}
  				else {
  					for( int i = 0 ; i<= n - 5 ; i+=2) {
  						long l = lcm(arr[i], arr[i+1]);
  						out.print(l/arr[i] + " " + -1*l/arr[i+1]+ " ");
  //						x.add(l/arr[i]);
  //						x.add( -1*l/arr[i+1]);
  					}
  					long l = lcm( arr[n-3] , arr[n-2]);
  					l = lcm( l , arr[n-1]);
  					out.print(-2*l/arr[n-3] + " " + l/arr[n-2] + " " + l/arr[n-1]);
  //					x.add(-2*l/arr[n-3] );
  //					x.add(l/arr[n-2]);
  //					x.add( l/arr[n-1]);
  				}
  //				out.println();
  //				out.println(x.size());
  //				long sum = 0;
  //				for( int i= 0 ;i< n;i++) {
  //					sum+=arr[i]*x.get(i);
  //					out.print(x.get(i)+" ");
  //				}
  //				out.println();
  //				out.println(   sum);
  				out.println();
  			}
  			out.flush();
  		}
  	
  		public static boolean ifpowof2(long n ) {
  			return ((n&(n-1)) == 0);
  		}
  		
  		public static int[] nextLargerElement(int[] arr, int n)	{ 
  			Stack<Integer> stack = new Stack<>();
  			int rtrn[] = new int[n];
  			rtrn[n-1] = -1;
  	        stack.push( n-1);
  	        for( int i = n-2 ;i >= 0 ; i--){
  	            int temp = arr[i];
  	            int lol = -1;
  	            while( !stack.isEmpty() && arr[stack.peek()] <= temp){
  	            	if(arr[stack.peek()] == temp ) {
  	            		lol = stack.peek();
  	            	}
  	                stack.pop();
  	            }
  	            if( stack.isEmpty()){
  	            	if( lol != -1) {
  	            		rtrn[i] = lol;
  	            	}
  	            	else {
  	            		rtrn[i] = -1;
  	            	}
  	            }
  	            else{
  	            	rtrn[i] = stack.peek();
  	            }
  	            stack.push( i);
  	        }
  	        return rtrn;
  		}
  		
  		static long gcd(long a, long b)
  		{
  			if (a == 0)
  				return b;
  			return gcd(b % a, a);
  		}
  		
  			   
  		 static long lcm(long a, long b)
  		 {
  			 return (a / gcd(a, b)) * b;
  		 }
  		 
  
  		 static long rightmostsetbit(long n) {
  			 return n&-n;
  		 }
  		 
  		 static long leftmostsetbit(long n)
  		    {
  		        long k = (long)(Math.log(n) / Math.log(2));
  		        return 1 << k;
  		    }
  	 
  		 static HashMap<Long,Long> primefactor( long n){
  			 HashMap<Long ,Long> hm = new HashMap<>();
  			 long temp = 0;
  			 while( n%2 == 0) {
  				 temp++;
  				 n/=2;
  			 }	
  			 if( temp!= 0) {
  				 hm.put( 2L, temp);
  			 }
  			 long c = (long)Math.sqrt(n);
  			 for( long i = 3 ; i <= c ; i+=2) {
  				 temp = 0;
  				 while( n% i == 0) {
  					 temp++;
  					 n/=i;
  				 }
  				 if( temp!= 0) {
  					 hm.put( i, temp);
  				 }
  	 		 }
  	 		 if( n!= 1) {
  	 			 hm.put( n , 1L);
  	 		 }
  	 		 return hm;	
  		 }
  		 
  		 @SuppressWarnings("unused")
  		private static ArrayList<Integer> allfactors(int abs) {
  			 HashMap<Integer,Integer> hm = new HashMap<>();
  			 ArrayList<Integer> rtrn = new ArrayList<>();
  			 for( int i = 2 ;i*i <= abs; i++) {
  				 if( abs% i == 0) {
  					 hm.put( i , 0);
  					 hm.put(abs/i, 0);
  				 }
  			 }
  			 for( int x : hm.keySet()) {
  				 rtrn.add(x);
  			 }
  			 
  			 if( abs != 0) {
  				 rtrn.add(abs);
  			 }
  			 
  			 return rtrn;
  		 }
  			
  	 
  		 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;
  			 }
  		 }	
  }