func_code_string: #include <bits/stdc++.h>   using namespace std;   void Speed() {     ios_base::sync_with_stdio(0);     cin.tie(0);     cout.tie(0);   }   struct xi {     long long a, b;   };   const int XS = 1e3 + 12;   const int second = 1e4 + 12;   const int M = 1e5 + 12;   const int L = 1e6 + 12;   const int XL = 1e7 + 12;   const long long INF1 = 1e9 + 7;   const long long INF2 = 1e12 + 7;   long long T, n;   void Tramp() {     cin >> n;     long long a[n + 12], b[n + 12];     for (int i = 1; i <= n; ++i) cin >> a[i];     for (int i = 1; i <= n; ++i) {       if (i & 1) {         b[i] = a[i + 1] * (-1);         b[i + 1] = a[i];       }     }     for (int i = 1; i <= n; ++i) cout << b[i] <<    ;     cout <<   n ;   }   int main() {     Speed();     cin >> T;     while (T--) Tramp();   }   