boost::container::multiset
// In header: <boost/container/set.hpp> template<typename InputIterator> multiset(ordered_range_t, InputIterator, InputIterator);
Deduction guide: allows a multiset to be constructed from an already ordered iterator range [first, last), deducing the key type from InputIterator and using the default comparator and allocator.
multiset
[first, last)
InputIterator