func_code_string: #include <bits/stdc++.h>   using namespace std;   const int INF = 2e9;   FILE* stream;   mt19937 rng(1337);   void solve() {     int n;     cin >> n;     vector<int> a(n);     for (int i = 0; i < int(n); i++) {       cin >> a[i];     }     vector<int> b(n);     for (int i = 0; i < int(n); i++) {       if (i % 2) {         b[i] = a[i - 1];       } else {         b[i] = -a[i + 1];       }     }     for (int i = 0; i < int(n); i++) cout << b[i] <<    ;     cout << endl;     return;   }   signed main() {     int t;     cin >> t;     while (t--) solve();     return 0;   }   