Compilare: main.cpp: In function 'int main()': main.cpp:26:23: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 26 | for (int i = 0; i < s.size() - 1; ++i) { | ~~^~~~~~~~~~~~~~ main.cpp:31:40: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 31 | while (right >= 0 && right < s.size() && is_correct(s[left], s[right])) { | ~~~~~~^~~~~~~~~~