foo.cc: In member function 'int SeqList::Search(int)':
foo.cc:14:30: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   14 |                 for(int i=0;i<seq.size();i++)
      |                             ~^~~~~~~~~~~
foo.cc: In member function 'std::vector<int> SeqList::Union(SeqList&) const':
foo.cc:24:35: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   24 |                 for (int i = 0; i < seq.size(); i++)
      |                                 ~~^~~~~~~~~~~~
foo.cc: In function 'int main()':
foo.cc:48:35: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   48 |                 for (int i = 0; i < res.size(); i++)
      |                                 ~~^~~~~~~~~~~~