/in/foo.cc: In function 'void get_maxd(int, int)':
/in/foo.cc:13:15: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for(int i=0;i<vec[id].size();i++)
              ~^~~~~~~~~~~~~~~
/in/foo.cc: In function 'void get_dfn(int, int, int)':
/in/foo.cc:27:15: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for(int i=0;i<vec[id].size();i++)
              ~^~~~~~~~~~~~~~~
/in/foo.cc: In function 'void solve(int, int)':
/in/foo.cc:44:15: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for(int i=0;i<vec[id].size();i++)
              ~^~~~~~~~~~~~~~~
/in/foo.cc:57:8: warning: unused variable 'afa' [-Wunused-variable]
    int afa=0;
        ^~~