combo.cpp: In function 'std::string guess_sequence(int)':
combo.cpp:22:17: warning: comparison of integer expressions of different signedness: 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} and 'int' [-Wsign-compare]
22 | if(last.size()==N) return last;
| ~~~~~~~~~~~^~~
combo.cpp:24:37: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
24 | if(it[0]!=last[0]&&press(last+it)==last.size()+1){
| ~~~~~~~~~~~~~~^~~~~~~~~~~~~~~