combo.cpp: In function 'std::string guess_sequence(int)':
combo.cpp:26:23: warning: comparison of integer expressions of different signedness: 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} and 'int' [-Wsign-compare]
26 | while (ret.size() != N) {
| ~~~~~~~~~~~^~~~
combo.cpp:30:18: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
30 | if (news == ret.size()) {
| ~~~~~^~~~~~~~~~~~~
combo.cpp:36:22: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
36 | if (news == ret.size()) ret += possible[1];
| ~~~~~^~~~~~~~~~~~~