combo.cpp: In function 'std::string guess_sequence(int)':
combo.cpp:8:14: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
8 | for(int k=0;k<a.size();k++){
| ~^~~~~~~~~
combo.cpp:15:14: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
15 | for(int k=0;k<a.size();k++){
| ~^~~~~~~~~
combo.cpp:22:14: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
22 | for(int k=0;k<a.size();k++){
| ~^~~~~~~~~