Compilare: main.cpp: In function 'int main()': main.cpp:51:23: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 51 | for (int i = 0; i < s2.size(); i++) { | ~~^~~~~~~~~~~ main.cpp:67:18: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 67 | if (cate == s2.size()) { | ~~~~~^~~~~~~~~~~~ main.cpp:82:21: warning: unused variable 'dr' [-Wunused-variable] 82 | int st = 0, dr; | ^~