Compilare: main.cpp: In function 'void generate_connections(std::string, std::unordered_map<std::__cxx11::basic_string<char>, std::set<char> >&)': main.cpp:13:19: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 13 | for(int i=0; i<a.length() - 2; i++){ | ~^~~~~~~~~~~~~~~ main.cpp: In function 'std::string solve(std::string, std::unordered_map<std::__cxx11::basic_string<char>, std::set<char> >&)': main.cpp:27:19: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 27 | for(int i=0; i<b.length()-2; i++){ | ~^~~~~~~~~~~~~