func_code_string: #include <bits/stdc++.h>   using namespace std;   int32_t main() {     ios_base::sync_with_stdio(false);     cin.tie(NULL);     cout.tie(NULL);     long long t;     cin >> t;     while (t--) {       long long n;       cin >> n;       long long arr[n];       for (long long i = 0; i < n; i++) {         cin >> arr[i];       }       long long b[n];       if (n % 2 == 0) {         for (long long i = 0; i < n - 1; i = i + 2) {           b[i] = arr[i + 1];           b[i + 1] = -1 * arr[i];         }         for (long long i = 0; i < n; i++) {           cout << b[i] <<    ;         }         cout <<   n ;       } else {         for (long long i = 3; i < n - 1; i = i + 2) {           b[i] = arr[i + 1];           b[i + 1] = -1 * arr[i];         }         if (arr[0] + arr[1] != 0) {           cout << -arr[2] <<     << -arr[2] <<     << arr[0] + arr[1] <<    ;         } else if (arr[1] + arr[2] != 0) {           cout << arr[1] + arr[2] <<     << -arr[0] <<     << -arr[0] <<    ;         } else {           cout << -arr[1] <<     << arr[0] + arr[2] <<     << -arr[1] <<    ;         }         for (long long i = 3; i < n; i++) {           cout << b[i] <<    ;         }         cout <<   n ;       }     }     return 0;   }   