Compilare: main.cpp: In function 'void solve()': main.cpp:18:22: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 18 | for(int i=0,j=0;i<a.size();i++,j++){ | ~^~~~~~~~~ main.cpp:20:21: warning: array subscript has type 'char' [-Wchar-subscripts] 20 | def[b[j]]=1; | ^