#include <bits/stdc++.h>
using namespace std;
using VI = vector<int>;
using VVI = vector<VI>;
using PII = pair<int, int>;
using LL = long long;
using VL = vector<LL>;
using VVL = vector<VL>;
using PLL = pair<LL, LL>;
using VS = vector<string>;
template <class S, class T>
istream& operator>>(istream& is, pair<S, T>& p) {
  return is >> p.first >> p.second;
}
template <class T>
istream& operator>>(istream& is, vector<T>& xs) {
  for (auto& x : xs) is >> x;
  return is;
}
template <class S, class T>
ostream& operator<<(ostream& os, const pair<S, T>& p) {
  return os << p.first << " " << p.second;
}
template <class T>
ostream& operator<<(ostream& os, const vector<T>& xs) {
  for (unsigned int i = 0; i < xs.size(); ++i) os << (i ? " " : "") << xs[i];
  return os;
}
template <class T>
void maxi(T& x, T y) {
  if (x < y) x = y;
}
template <class T>
void mini(T& x, T y) {
  if (x > y) x = y;
}
void debug(istringstream&) {}
template <char sep = ',', class Head, class... Tail>
void debug(istringstream& iss, Head&& head, Tail&&... tail) {
  string name;
  getline(iss, name, ',');
  cout << sep << name << "=" << head;
  debug(iss, forward<Tail>(tail)...);
}
void init_io(int argc, char* argv[]) {
  cin.tie(0);
  ios_base::sync_with_stdio(false);
}
const double EPS = 1e-10;
const double PI = acos(-1.0);
const LL MOD = 1e9 + 7;
int main(int argc, char* argv[]) {
  init_io(argc, argv);
  int T;
  cin >> T;
  while (T--) {
    int N;
    cin >> N;
    VI xs(N);
    cin >> xs;
    VI ans(N);
    for (int i = (0); i < (N / 2); ++i) {
      ans[i] = xs[N - 1 - i];
      ans[N - 1 - i] = -xs[i];
    }
    cout << ans << endl;
  }
  return 0;
}
