Compilare: main.cpp: In function 'void solve()': main.cpp:27:29: warning: comparison of integer expressions of different signedness: 'long long int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 27 | for (long long i = 0; i < x.size(); i++) | ~~^~~~~~~~~~