Compilare: main.cpp: In function 'int main()': main.cpp:25:23: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 25 | for (int i = 0; i < s.size() - 1; ++i) { | ~~^~~~~~~~~~~~~~ main.cpp:28:47: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 28 | while (left_idx >= 0 && right_idx < s.size() && is_correct(s[left_idx], s[right_idx])) { | ~~~~~~~~~~^~~~~~~~~~ main.cpp:40:27: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 40 | for (int i = 0; i < s.size(); ++i) { | ~~^~~~~~~~~~ main.cpp:49:47: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 49 | while (left >= 0 && right < s.size() && is_correct(s[left], s[right])) { | ~~~~~~^~~~~~~~~~ main.cpp:61:23: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 61 | for (int i = 0; i < s.size(); ++i) { | ~~^~~~~~~~~~