#include <bits/stdc++.h>
using namespace std;
signed main() {
  ios_base::sync_with_stdio(0);
  cin.tie(0), cout.tie(0);
  long long t;
  cin >> t;
  while (t--) {
    long long n;
    cin >> n;
    vector<long long> a(n);
    for (long long i = 0; i < n; ++i) {
      cin >> a[i];
    }
    for (long long i = 0; i < n; ++i) {
      if (i < n / 2) {
        cout << -a[n - i - 1] << ' ';
      } else {
        cout << a[n - i - 1] << ' ';
      }
    }
    cout << '\n';
  }
}
