combo.cpp: In function 'std::string guess_sequence(int)':
combo.cpp:28:18: warning: comparison of integer expressions of different signedness: 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} and 'int' [-Wsign-compare]
28 | while (S.size() <= N - 2) {
| ~~~~~~~~~^~~~~~~~
combo.cpp:31:10: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
31 | if (F3 >= S.size() + 2) {
| ~~~^~~~~~~~~~~~~~~
combo.cpp:34:11: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
34 | if (F4 == S.size() + 2) S += rev(0, 0);
| ~~~^~~~~~~~~~~~~~~
combo.cpp:35:11: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
35 | if (F4 == S.size() + 1) S += rev(0, 1);
| ~~~^~~~~~~~~~~~~~~
combo.cpp:36:11: 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 (F4 == S.size() + 0) S += rev(1, 2);
| ~~~^~~~~~~~~~~~~~~
combo.cpp:38:15: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
38 | else if (F3 == S.size() + 1) {
| ~~~^~~~~~~~~~~~~~~
combo.cpp:41:11: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
41 | if (F4 == S.size() + 2) S += rev(1, 0);
| ~~~^~~~~~~~~~~~~~~
combo.cpp:42:11: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
42 | if (F4 == S.size() + 1) S += rev(1, 1);
| ~~~^~~~~~~~~~~~~~~
combo.cpp:43:11: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
43 | if (F4 == S.size() + 0) S += rev(0, 2);
| ~~~^~~~~~~~~~~~~~~
combo.cpp:50:15: warning: comparison of integer expressions of different signedness: 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} and 'int' [-Wsign-compare]
50 | if (S.size() == N - 1) {
| ~~~~~~~~~^~~~~~~~
combo.cpp:56:16: warning: comparison of integer expressions of different signedness: 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} and 'int' [-Wsign-compare]
56 | if (S.size() == N - 1) S += I[2];
| ~~~~~~~~~^~~~~~~~