combo.cpp: In function 'std::string guess_sequence(int)':
combo.cpp:20:23: warning: comparison of integer expressions of different signedness: 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} and 'int' [-Wsign-compare]
20 | while (sol.size() < N){
| ~~~~~~~~~~~^~~
combo.cpp:21:26: warning: comparison of integer expressions of different signedness: 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} and 'int' [-Wsign-compare]
21 | if (sol.size()+1 == N){
| ~~~~~~~~~~~~~^~~~
combo.cpp:33:19: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
33 | if (x == sol.size())sol += c[2];
| ~~^~~~~~~~~~~~~
combo.cpp:34:24: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
34 | else if (x == sol.size()+1)sol += c[1];
| ~~^~~~~~~~~~~~~~~