Compilare: user.cpp: In member function ‘bool cmp::operator()(std::pair<int, char>, std::pair<int, char>)’: user.cpp:23:35: warning: array subscript has type ‘char’ [-Wchar-subscripts] return d[x.first][x.second] > d[y.first][y.second]; ^ user.cpp:23:58: warning: array subscript has type ‘char’ [-Wchar-subscripts] return d[x.first][x.second] > d[y.first][y.second]; ^ user.cpp: In function ‘int main()’: user.cpp:72:40: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i = 0; i < v[nod].size(); i++) ^