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