func_code_string: #include <bits/stdc++.h>   using namespace std;   vector<bool> prime(1001, true);   void sieve() {     prime[0] = false;     prime[1] = false;     for (int i = 2; i <= 1000; i++) {       if (prime[i]) {         int j = 2;         while (i * j <= 1000) {           prime[i * j] = false;           j++;         }       }     }   }   long long int ceil_sqrt(long long int a) {     long long int i = 1;     while (i * i < a) i++;     return i;   }   void solve() {     int n;     cin >> n;     int a[n];     for (int i = 0; i < n; i++) cin >> a[i];     for (int i = 0; i < n; i += 2) cout << a[i + 1] <<     << -1 * a[i] <<    ;     cout << endl;   }   int main() {     ios_base::sync_with_stdio(false);     cin.tie(0);     cout.tie(0);     int t;     cin >> t;     while (t--) solve();     return 0;   }   