/in/foo.cc: In function 'bool DFS(int)':
/in/foo.cc:23:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for (int i = 0; i < que[st].size(); i++)
                     ~~^~~~~~~~~~~~~~~~
/in/foo.cc: In function 'int main()':
/in/foo.cc:81:30: warning: format '%d' expects argument of type 'int', but argument 2 has type 'std::vector<int>::size_type {aka long unsigned int}' [-Wformat=]
     printf("%d\n", ans.size());
                              ^
/in/foo.cc:82:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for (int i = 0; i < ans.size(); i++)
                     ~~^~~~~~~~~~~~