17	38	C:\（打码）\P3853 路标设置.cpp	[Error] conversion from 'std::set<int>::reverse_iterator {aka std::reverse_iterator<std::_Rb_tree_const_iterator<int> >}' to non-scalar type 'std::set<int>::iterator {aka std::_Rb_tree_const_iterator<int>}' requested

这个报错是什么意思，好长，我看不懂awa