Compilare: main.cpp: In function 'int main()': main.cpp:32:14: warning: comparison of integer expressions of different signedness: 'long long int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 32 | for(i=0;i<a.size();i++) v[a[i]-'a'].push_back(i+1); | ~^~~~~~~~~ main.cpp:34:14: warning: comparison of integer expressions of different signedness: 'long long int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 34 | for(i=0;i<b.size();i++){ | ~^~~~~~~~~