Luna::set_union

template <typename _InputIt1, typename _InputIt2, typename _OutputIt, typename _Compare>
_OutputIt set_union(_InputIt1 first1, _InputIt1 last1, _InputIt2 first2, _InputIt2 last2, _OutputIt d_first, _Compare comp)

Constructs a sorted union beginning at the destination range consisting of the set of elements present in one or both sorted ranges.

Parameters

• in first1

  The iterator to the first element of the first range.

• in last1

  The iterator to the one-past-last element of the first range.

• in first2

  The iterator to the first element of the second range.

• in last2

  The iterator to the one-past-last element of the second range.

• in d_first

  The iterator to the first element of the destination range.

• in comp

  The user-provided binary predicate which returns ​true if the first argument is less than the second.

Remark

If [first1, last1) contains m elements that are equivalent to each otherand [first2, last2) contains n elements that are equivalent to them, then all m elements will be copied from [first1, last1) to the output range, preserving order, and then the final max(n - m, 0) elements will be copied from [first2, last2) to the output range, also preserving order.

Valid Usage

• Elements in the ranges specified by [first1, last1) and [first2, last2) must be sorted in non-descending order.

• comp must have the following function signature: bool comp(const Type& a, const Type& b), where Type is the value type of both _InputIt1 and _InputIt2.