september.cpp: In function 'int solve(int, int, std::vector<int>, std::vector<std::vector<int> >)':
september.cpp:39:23: error: no match for 'operator=' (operand types are 'std::__detail::_Node_iterator<int, true, false>' and 'std::unordered_set<int>::size_type' {aka 'long unsigned int'})
39 | it=req.erase(c);
| ^
In file included from /usr/include/c++/11/bits/hashtable.h:35,
from /usr/include/c++/11/unordered_map:46,
from /usr/include/c++/11/functional:61,
from /usr/include/c++/11/pstl/glue_algorithm_defs.h:13,
from /usr/include/c++/11/algorithm:74,
from /usr/include/x86_64-linux-gnu/c++/11/bits/stdc++.h:65,
from september.cpp:1:
/usr/include/c++/11/bits/hashtable_policy.h:317:12: note: candidate: 'constexpr std::__detail::_Node_iterator<int, true, false>& std::__detail::_Node_iterator<int, true, false>::operator=(const std::__detail::_Node_iterator<int, true, false>&)'
317 | struct _Node_iterator
| ^~~~~~~~~~~~~~
/usr/include/c++/11/bits/hashtable_policy.h:317:12: note: no known conversion for argument 1 from 'std::unordered_set<int>::size_type' {aka 'long unsigned int'} to 'const std::__detail::_Node_iterator<int, true, false>&'
/usr/include/c++/11/bits/hashtable_policy.h:317:12: note: candidate: 'constexpr std::__detail::_Node_iterator<int, true, false>& std::__detail::_Node_iterator<int, true, false>::operator=(std::__detail::_Node_iterator<int, true, false>&&)'
/usr/include/c++/11/bits/hashtable_policy.h:317:12: note: no known conversion for argument 1 from 'std::unordered_set<int>::size_type' {aka 'long unsigned int'} to 'std::__detail::_Node_iterator<int, true, false>&&'