Compilare: main.cpp: In function 'bool can_solve(const std::string&, int)': main.cpp:16:17: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 16 | while (i<str.size()&&j<key.size()) { | ~^~~~~~~~~~~ main.cpp:16:31: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 16 | while (i<str.size()&&j<key.size()) { | ~^~~~~~~~~~~ main.cpp:27:18: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 27 | return j == key.size(); | ~~^~~~~~~~~~~~~