Compilare: main.cpp: In function 'int main()': main.cpp:27:23: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 27 | for (int i = 0; i < s.size() - 1; ++i) { | ~~^~~~~~~~~~~~~~ main.cpp:36:72: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 36 | while (is_correct(s[left], s[right]) && left >= 0 && right < s.size()) { | ~~~~~~^~~~~~~~~~ main.cpp:23:9: warning: unused variable 'n' [-Wunused-variable] 23 | int n; | ^ main.cpp:26:20: warning: unused variable 'counter' [-Wunused-variable] 26 | int maxim = 0, counter = 0; | ^~~~~~~