Compilare: user.cpp: In function ‘bool checkAxis(const P&, const P&)’: user.cpp:57:17: warning: unused variable ‘built’ [-Wunused-variable] static bool built = [&]() { ^~~~~ user.cpp: In function ‘int main()’: user.cpp:70:34: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("dmg.in", "r", stdin); ^ user.cpp:71:36: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("dmg.out", "w", stdout); ^