/in/foo.cc: In member function 'int SeqList::Search(int)':
/in/foo.cc:14:16: 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&) const':
/in/foo.cc:24:21: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
   for (int i = 0; i < seq.size(); i++)
                   ~~^~~~~~~~~~~~
/in/foo.cc: In function 'int main()':
/in/foo.cc:48:21: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
   for (int i = 0; i < res.size(); i++)
                   ~~^~~~~~~~~~~~