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.io.*;
  import java.util.*;
  import java.lang.*;
  
  public class TaskD {
      public static void  setVal(int[] ans,int[] a,int index,int val,int sign){
          long newVal = a[index]*(long)val;
          if((newVal<0 && sign<0 )|| (newVal>0 && sign>0)){
              ans[index] = val;
          }
          else{
              ans[index] = -1*val;
          }
      }
      public static void solve(FastReader in,PrintWriter out,int nTestCase) {
          int n = in.nextInt();
          int[] a = in.readArray(n);
          int[] ans = new int[n];
          ArrayList<Pair> sortedPairs = new ArrayList<>();
          for(int i=0;i<n;i++){
              sortedPairs.add(new Pair(Math.abs(a[i]),i));
          }
          Collections.sort(sortedPairs);
          int start = 0;
          if(sortedPairs.size()%2==1){
              start = 3;
              setVal(ans,a,sortedPairs.get(0).b,(int)(sortedPairs.get(1).a+sortedPairs.get(2).a),-1);
              setVal(ans,a,sortedPairs.get(1).b,(int)(sortedPairs.get(0).a),1);
              setVal(ans,a,sortedPairs.get(2).b,(int)(sortedPairs.get(0).a),1);
          }
          for(int i=start;i<sortedPairs.size();i+=2){
              long mul = (sortedPairs.get(i).a)*(long)(sortedPairs.get(i+1).a);
              setVal(ans,a,sortedPairs.get(i).b,sortedPairs.get(i+1).a,-1);
              setVal(ans,a,sortedPairs.get(i+1).b,sortedPairs.get(i).a,1);
          }
          for(int i:ans) out.print(i+" ");
          out.println();
      }
      public static void main(String[] args) {
          FastReader in = new FastReader();
          PrintWriter out = new PrintWriter(System.out);
          int T = 1;
          T = in.nextInt();
          for(int tt=1;tt<=T;tt++) {
              solve(in,out,tt);
          }
          out.close();
      }
      static final Random random=new Random();
      static void fastSort(int[] a) {
          int n=a.length;//shuffle, then sort
          for (int i=0; i<n; i++) {
              int oi=random.nextInt(n);
              int temp=a[oi];
              a[oi]=a[i]; a[i]=temp;
          }
          Arrays.sort(a);
      }
      static void fastSort(char[] a) {
          int n=a.length;//shuffle, then sort
          for (int i=0; i<n; i++) {
              int oi=random.nextInt(n);
              char temp=a[oi];
              a[oi]=a[i]; a[i]=temp;
          }
          Arrays.sort(a);
      }
      static int gcd(int a, int b)
      {
          if (b == 0)
              return a;
          return gcd(b, a % b);
      }
      static class Pair implements Comparable<Pair>{
          int  a;
          int  b;
          public Pair(int  a, int  b) {
              this.a = a;
              this.b = b;
          }
          public int compareTo(Pair o) {
              if(this.a==o.a)
                  return (int)(this.b - o.b);
              return (int)(this.a - o.a);
          }
      }
      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;
          }
  
          public int[] readArray(int n) {
              int[] a=new int[n];
              for (int i=0; i<n; i++) a[i]=nextInt();
              return a;
          }
      }
  }
  
  