24 Containers library [containers]

24.4 Associative containers [associative]

24.4.5 Class template multimap [multimap]

24.4.5.2 Constructors [multimap.cons]

explicit multimap(const Compare& comp, const Allocator& = Allocator());
Effects: Constructs an empty multimap using the specified comparison object and allocator.
Complexity: Constant.
template<class InputIterator> multimap(InputIterator first, InputIterator last, const Compare& comp = Compare(), const Allocator& = Allocator());
Effects: Constructs an empty multimap using the specified comparison object and allocator, and inserts elements from the range [first, last).
Complexity: Linear in N if the range [first, last) is already sorted using comp and otherwise , where N is last - first.
template<container-compatible-range<value_type> R> multimap(from_range_t, R&& rg, const Compare& comp = Compare(), const Allocator& = Allocator());
Effects: Constructs an empty multimap using the specified comparison object and allocator, and inserts elements from the range rg.
Complexity: Linear in N if rg is already sorted using comp and otherwise , where N is ranges​::​distance(rg).