combo.cpp: In function 'std::string guess_sequence(int)':
combo.cpp:19:7: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
19 | if(k==S.size()){
| ~^~~~~~~~~~
combo.cpp:22:12: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
22 | else if(k==S.size()+1){
| ~^~~~~~~~~~~~