/in/foo.cc: In function 'int create_tree(const string&)':
/in/foo.cc:52:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for(int i = 0; i < s.length(); i++) cnt[s[i]]++;
                    ~~^~~~~~~~~~~~
/in/foo.cc:52:49: warning: array subscript has type 'char' [-Wchar-subscripts]
     for(int i = 0; i < s.length(); i++) cnt[s[i]]++;
                                                 ^
/in/foo.cc: In function 'int ask(int, int)':
/in/foo.cc:80:38: warning: array subscript has type 'char' [-Wchar-subscripts]
         return dep * cnt[tree[from].c];
                                      ^