combo.cpp: In function 'std::string guess_sequence(int)':
combo.cpp:34:21: 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 (s.size() < n) {
      |            ~~~~~~~~~^~~
combo.cpp:40:15: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   40 |         if (x == s.size()) {
      |             ~~^~~~~~~~~~~
combo.cpp:43:20: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   43 |         else if (x == s.size() + 1) {
      |                  ~~^~~~~~~~~~~~~~~