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: #include <bits/stdc++.h>
  using namespace std;
  long long gcd(long long a, long long b) {
    if (b > a) {
      return gcd(b, a);
    }
    if (b == 0) {
      return a;
    }
    return gcd(b, a % b);
  }
  void swap(long long &x, long long &y) {
    long long temp = x;
    x = y;
    y = temp;
  }
  long long expo(long long a, long long b, long long mod) {
    long long res = 1;
    a %= mod;
    while (b > 0) {
      if (b & 1) res = (res * a) % mod;
      a = (a * a) % mod;
      b = b >> 1;
    }
    return res;
  }
  long long mminvprime(long long a, long long b) { return expo(a, b - 2, b); }
  void precision(long long a) { cout << setprecision(a) << fixed; }
  long long mod_mul(long long a, long long b, long long m) {
    a = a % m;
    b = b % m;
    return (((a * b) % m) + m) % m;
  }
  long long mod_add(long long a, long long b, long long m) {
    a = a % m;
    b = b % m;
    return (((a + b) % m) + m) % m;
  }
  long long mod_sub(long long a, long long b, long long m) {
    a = a % m;
    b = b % m;
    return (((a - b) % m) + m) % m;
  }
  long long mod_div(long long a, long long b, long long m) {
    a = a % m;
    b = b % m;
    return (mod_mul(a, mminvprime(b, m), m) + m) % m;
  }
  vector<long long> sieve(long long n) {
    long long *ssssssssssssssssasdqad = new long long[n + 1]();
    vector<long long> vect;
    for (long long i = 2; i <= n; i++)
      if (ssssssssssssssssasdqad[i] == 0) {
        vect.push_back(i);
        for (long long j = 2 * i; j <= n; j += i) ssssssssssssssssasdqad[j] = 1;
      }
    return vect;
  }
  template <typename Node>
  struct SparseTable {
    vector<vector<Node>> table;
    vector<long long> logValues;
    long long n;
    long long maxLog;
    vector<long long> a;
    SparseTable(long long n1, vector<long long> &ssssssssssssssssasdqad) {
      n = n1;
      a = ssssssssssssssssasdqad;
      table.resize(n);
      logValues.resize(n + 1);
      maxLog = log2(n);
      logValues[1] = 0;
      for (long long i = 2; i <= n; i++) {
        logValues[i] = logValues[i / 2] + 1;
      }
      for (long long i = 0; i < n; i++) {
        table[i].resize(maxLog + 1);
        fill(table[i].begin(), table[i].end(), Node());
      }
      build();
    }
    void build() {
      for (long long i = 0; i < n; i++) {
        table[i][0] = Node(a[i]);
      }
      for (long long i = 1; i <= maxLog; i++) {
        for (long long j = 0; (j + (1 << i)) <= n; j++) {
          table[j][i].merge(table[j][i - 1], table[j + (1 << (i - 1))][i - 1]);
        }
      }
    }
    Node queryNormal(long long left, long long right) {
      Node sssasdsssssssssssssasdqad = Node();
      for (long long j = logValues[right - left + 1]; j >= 0; j--) {
        if ((1 << j) <= right - left + 1) {
          sssasdsssssssssssssasdqad.merge(sssasdsssssssssssssasdqad,
                                          table[left][j]);
          left += (1 << j);
        }
      }
      return sssasdsssssssssssssasdqad;
    }
    Node queryIdempotent(long long left, long long right) {
      long long j = logValues[right - left + 1];
      Node sssasdsssssssssssssasdqad = Node();
      sssasdsssssssssssssasdqad.merge(table[left][j],
                                      table[right - (1 << j) + 1][j]);
      return sssasdsssssssssssssasdqad;
    }
  };
  struct Node1 {
    long long val;
    Node1() { val = 0; }
    Node1(long long v) { val = v; }
    void merge(Node1 &l, Node1 &r) { val = min(l.val, r.val); }
  };
  void solve() {
    long long n;
    cin >> n;
    long long sssasdsssssssssssssasdqadaa[n];
    for (long long i = 0; i < n; i++) {
      cin >> sssasdsssssssssssssasdqadaa[i];
    }
    vector<long long> sssasdsssssssssssssasdqad;
    if (n % 2 == 0) {
      for (long long i = 0; i < n; i += 2) {
        sssasdsssssssssssssasdqad.push_back(sssasdsssssssssssssasdqadaa[i + 1]);
        sssasdsssssssssssssasdqad.push_back(-1 * sssasdsssssssssssssasdqadaa[i]);
      }
    } else {
      if (sssasdsssssssssssssasdqadaa[0] + sssasdsssssssssssssasdqadaa[1] != 0) {
        sssasdsssssssssssssasdqad.push_back(sssasdsssssssssssssasdqadaa[2]);
        sssasdsssssssssssssasdqad.push_back(sssasdsssssssssssssasdqadaa[2]);
        sssasdsssssssssssssasdqad.push_back(
            -1 *
            (sssasdsssssssssssssasdqadaa[0] + sssasdsssssssssssssasdqadaa[1]));
      } else {
        sssasdsssssssssssssasdqad.push_back(sssasdsssssssssssssasdqadaa[2]);
        sssasdsssssssssssssasdqad.push_back(-1 * sssasdsssssssssssssasdqadaa[2]);
        sssasdsssssssssssssasdqad.push_back(
            -1 *
            (sssasdsssssssssssssasdqadaa[0] - sssasdsssssssssssssasdqadaa[1]));
      }
      for (long long i = 3; i < n; i += 2) {
        sssasdsssssssssssssasdqad.push_back(sssasdsssssssssssssasdqadaa[i + 1]);
        sssasdsssssssssssssasdqad.push_back(-1 * sssasdsssssssssssssasdqadaa[i]);
      }
    }
    for (auto i : sssasdsssssssssssssasdqad) {
      cout << i << " ";
    }
    cout << "\n";
  }
  signed main() {
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);
    long long t = 1;
    cin >> t;
    while (t--) {
      solve();
    }
    return 0;
  }
  