How to change a container elements in another 'temporary' container - c++

Question

I have a temporary list that needs to change its elements and erase() them from the list as a way of marking them as done.
std::list<Vertex> temp {vertices.begin(), vertices.end()};
I've tried using Vertex& and Vertex* without success, and the second one makes the code very messy.
What is the proper way to do this? Thanks in advance
Edit: surrounding code
int label = 1;
// change elements without affecting temporary list
std::list<Vertex*> unlabeledVertices {graph.vertices.begin(), graph.vertices.end()};
for (auto iter = unlabeledVertices.begin(); iter != unlabeledVertices.end(); ++label) {
(*iter)->label = label;
// temporary list
std::list<Vertex*> currentLabelVertices;
currentLabelVertices.push_back(*iter);
// check if we can label any other vertex with the current color
auto nestedIter = iter;
for (nestedIter++; nestedIter != unlabeledVertices.end(); ) {
// checking current vertex against any other colored vertex
if (std::none_of(currentLabelVertices.begin(), currentLabelVertices.end(),
[=](const Vertex* v){ return (*nestedIter)->isConnected(*v); })) {
(*nestedIter)->label = label;
currentLabelVertices.push_back(*nestedIter);
nestedIter = unlabeledVertices.erase(nestedIter);
}
else {
nestedIter++;
}
}
iter = unlabeledVertices.erase(iter);
}
Error message:
/usr/bin/g++ -fdiagnostics-color=always -g /home/etzl/projects/c-cpp/test/*.cc -o exec
In file included from /usr/include/x86_64-linux-gnu/c++/10/bits/c++allocator.h:33,
from /usr/include/c++/10/bits/allocator.h:46,
from /usr/include/c++/10/string:41,
from /usr/include/c++/10/bits/locale_classes.h:40,
from /usr/include/c++/10/bits/ios_base.h:41,
from /usr/include/c++/10/ios:42,
from /usr/include/c++/10/ostream:38,
from /usr/include/c++/10/iostream:39,
from /home/etzl/projects/c-cpp/test/main.cc:1:
/usr/include/c++/10/ext/new_allocator.h: In instantiation of ‘void __gnu_cxx::new_allocator<_Tp>::construct(_Up*, _Args&& ...) [with _Up = Vertex*; _Args = {Vertex&}; _Tp = std::_List_node<Vertex*>]’:
/usr/include/c++/10/bits/alloc_traits.h:512:17: required from ‘static void std::allocator_traits<std::allocator<_CharT> >::construct(std::allocator_traits<std::allocator<_CharT> >::allocator_type&, _Up*, _Args&& ...) [with _Up = Vertex*; _Args = {Vertex&}; _Tp = std::_List_node<Vertex*>; std::allocator_traits<std::allocator<_CharT> >::allocator_type = std::allocator<std::_List_node<Vertex*> >]’
/usr/include/c++/10/bits/stl_list.h:637:33: required from ‘std::__cxx11::list<_Tp, _Alloc>::_Node* std::__cxx11::list<_Tp, _Alloc>::_M_create_node(_Args&& ...) [with _Args = {Vertex&}; _Tp = Vertex*; _Alloc = std::allocator<Vertex*>; std::__cxx11::list<_Tp, _Alloc>::_Node = std::__cxx11::list<Vertex*>::_Node]’
/usr/include/c++/10/bits/stl_list.h:1911:32: required from ‘void std::__cxx11::list<_Tp, _Alloc>::_M_insert(std::__cxx11::list<_Tp, _Alloc>::iterator, _Args&& ...) [with _Args = {Vertex&}; _Tp = Vertex*; _Alloc = std::allocator<Vertex*>; std::__cxx11::list<_Tp, _Alloc>::iterator = std::__cxx11::list<Vertex*>::iterator]’
/usr/include/c++/10/bits/stl_list.h:1227:19: required from ‘void std::__cxx11::list<_Tp, _Alloc>::emplace_back(_Args&& ...) [with _Args = {Vertex&}; _Tp = Vertex*; _Alloc = std::allocator<Vertex*>]’
/usr/include/c++/10/bits/stl_list.h:1840:18: required from ‘void std::__cxx11::list<_Tp, _Alloc>::_M_initialize_dispatch(_InputIterator, _InputIterator, std::__false_type) [with _InputIterator = std::_List_iterator<Vertex>; _Tp = Vertex*; _Alloc = std::allocator<Vertex*>]’
/usr/include/c++/10/bits/stl_list.h:806:26: required from ‘std::__cxx11::list<_Tp, _Alloc>::list(_InputIterator, _InputIterator, const allocator_type&) [with _InputIterator = std::_List_iterator<Vertex>; <template-parameter-2-2> = void; _Tp = Vertex*; _Alloc = std::allocator<Vertex*>; std::__cxx11::list<_Tp, _Alloc>::allocator_type = std::allocator<Vertex*>]’
/home/etzl/projects/c-cpp/test/main.cc:58:87: required from here
/usr/include/c++/10/ext/new_allocator.h:150:4: error: cannot convert ‘Vertex’ to ‘Vertex*’ in initialization
150 | { ::new((void *)__p) _Up(std::forward<_Args>(__args)...); }
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Build finished with error(s)

Answer 1

You should use std::unordered_set<Vertex*> currentLabelVertices instead of a list. It gives O(1) lookup instead of the O(n) solution you have with std::none_of().
Your other problem is here:
std::list<Vertex*> unlabeledVertices {graph.vertices.begin(), graph.vertices.end()};
It doesn't compile because graph.vertices contains Vertex instances, not pointers. The fix is simple:
std::list<Vertex*> unlabeledVertices;
for (auto& vertex : graph.vertices)
unlabeledVertices.push_back(&vertex);