Compilare: main.cpp: In function 'int main()': main.cpp:13:14: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 13 | for(i=0;i<s.size();i++){ | ~^~~~~~~~~ main.cpp:15:20: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 15 | while(i<s.size() && s[i]==')'){ | ~^~~~~~~~~ main.cpp:42:20: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 42 | while(i<s.size() && s[i]==')'){ | ~^~~~~~~~~ main.cpp:50:14: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::__cxx11::basic_string<char> >::size_type' {aka 'long unsigned int'} [-Wsign-compare] 50 | for(i=0;i<a.size();i++) | ~^~~~~~~~~