combo.cpp: In function 'std::string guess_sequence(int)':
combo.cpp:19:18: warning: comparison of integer expressions of different signedness: 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} and 'int' [-Wsign-compare]
19 | while(ret.size()<N) {
| ~~~~~~~~~~^~
combo.cpp:20:18: warning: comparison of integer expressions of different signedness: 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} and 'int' [-Wsign-compare]
20 | if(ret.size()+1==N) {
| ~~~~~~~~~~~~^~~
combo.cpp:27:11: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
27 | if(temp==ret.size()) ret.push_back(S[2]);
| ~~~~^~~~~~~~~~~~
combo.cpp:28:16: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
28 | else if(temp==ret.size()+1) {
| ~~~~^~~~~~~~~~~~~~
combo.cpp:30:12: 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(temp==ret.size()) ret.push_back(S[0]), ret.push_back(S[2]);
| ~~~~^~~~~~~~~~~~
combo.cpp:31:17: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
31 | else if(temp==ret.size()+1) ret.push_back(S[1]), ret.push_back(S[2]);
| ~~~~^~~~~~~~~~~~~~
combo.cpp:36:12: 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(temp==ret.size()) ret.push_back(S[1]), ret.push_back(S[0]);
| ~~~~^~~~~~~~~~~~
combo.cpp:37:17: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
37 | else if(temp==ret.size()+1) ret.push_back(S[0]), ret.push_back(S[0]);
| ~~~~^~~~~~~~~~~~~~
combo.cpp:8:6: warning: unused variable 'i' [-Wunused-variable]
8 | int i;
| ^