combo.cpp: In function 'std::string guess_sequence(int)':
combo.cpp:34:23: warning: comparison of integer expressions of different signedness: 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} and 'int' [-Wsign-compare]
34 | while(prefix.size() < N-1){
| ~~~~~~~~~~~~~~^~~~~
combo.cpp:36:14: 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(coins == prefix.size()+1){
| ~~~~~~^~~~~~~~~~~~~~~~~~
combo.cpp:39:19: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
39 | else if(coins == prefix.size()+2){
| ~~~~~~^~~~~~~~~~~~~~~~~~