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