func_code_string: #include <bits/stdc++.h>   using namespace std;   int main() {     long long t;     cin >> t;     while (t--) {       long long n;       cin >> n;       long long a[n + 1];       for (int i = 1; i <= n; i++) {         cin >> a[i];       }       for (int i = 1; i <= n; i += 2) {         cout << a[n - i + 1] * -1 <<     << a[n - i] <<    ;       }       cout <<   n ;     }     return 0;   }   