Compilare: main.cpp: In function 'int main()': main.cpp:27:18: 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<a.size();i++) v[i]=a[i]-'a'; | ~^~~~~~~~~ main.cpp:28:18: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 28 | for(int i=0;i<b.size();i++) fr[b[i]-'a']++; | ~^~~~~~~~~ main.cpp:85:18: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 85 | for(int i=0;i<a.size();i++) | ~^~~~~~~~~