In constructor 
  reverse_iterator<__normal_iterator<string*, vector<string> > >
  ::reverse_iterator(const reverse_iterator<_Iter>&)

no matching function for call to 
__normal_iterator<string*, vector<string> >
  ::__normal_iterator(__normal_iterator<const string*, vector<string> >)

candidates are
  ::__normal_iterator(const string* &) 
  ::__normal_iterator() 
  ::__normal_iterator(const __normal_iterator<string*, vector<string> >&)

-- triggered by:
   vector<string> const & a;
   typedef vector<string>::reverse_iterator riter;

   riter last = a.rbegin() + (a.size() - encloser_last_search);