Compilare: main.cpp: In function 'int main()': main.cpp:20:15: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 20 | for(i=0; i<s.size(); i++) | ~^~~~~~~~~ main.cpp:27:30: warning: array subscript has type 'char' [-Wchar-subscripts] 27 | v[i]=v[st.top()]=1; | ~~~~~~^~ main.cpp:37:15: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 37 | for(i=0; i<s.size(); i++) | ~^~~~~~~~~