foo.cc: In member function 'void seqlist::unionsolve(seqlist&)':
foo.cc:18:16: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   18 |         while(i<list.size()&&j<b.list.size())
      |               ~^~~~~~~~~~~~
foo.cc:18:31: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   18 |         while(i<list.size()&&j<b.list.size())
      |                              ~^~~~~~~~~~~~~~
foo.cc:25:16: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   25 |         while(i<list.size())    u.push_back(list[i++]);
      |               ~^~~~~~~~~~~~
foo.cc:26:16: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   26 |         while(j<b.list.size())  u.push_back(b.list[j++]);
      |               ~^~~~~~~~~~~~~~
foo.cc: In member function 'int seqlist::deleteself(std::vector<int>&)':
foo.cc:38:22: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   38 |         for(int i=1;i<a.size();i++)
      |                     ~^~~~~~~~~