/in/foo.cc: In member function 'int SeqList::Search(int)':
/in/foo.cc:16:21: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
   for (int i = 0; i < seq.size(); i++)
                   ~~^~~~~~~~~~~~
/in/foo.cc: In member function 'std::vector<int> SeqList::Union(SeqList&)':
/in/foo.cc:42:21: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
   for (int i = 0; i < seq.size(); i++)
                   ~~^~~~~~~~~~~~
/in/foo.cc:46:21: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
   for (int i = 0; i < obj.seq.size(); i++)
                   ~~^~~~~~~~~~~~~~~~
/in/foo.cc: In function 'int main()':
/in/foo.cc:71:20: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for (int i = 0; i < res.size(); i++)
                  ~~^~~~~~~~~~~~