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std::ranges::sort_heap(3)      C++ Standard Libary     std::ranges::sort_heap(3)

NAME
     std::ranges::sort_heap - std::ranges::sort_heap

Synopsis
	Defined in header <algorithm>
	Call signature
	template< std::random_access_iterator I, std::sentinel_for<I> S,

		  class Comp = ranges::less, class Proj = std::identity >
	requires  std::sortable<I,  Comp, Proj> 			     (1)
     (since C++20)
	constexpr I

	    sort_heap( I first, S last, Comp comp = {}, Proj proj = {} );
	template< ranges::random_access_range R, class Comp =
	ranges::less,

		  class Proj = std::identity  > 			     (2)
     (since C++20)
	requires std::sortable<ranges::iterator_t<R>, Comp, Proj>
	constexpr ranges::borrowed_iterator_t<R>

	    sort_heap( R&& r, Comp comp = {}, Proj proj = {} );

	Converts the max heap [first, last) into a sorted range in ascending or-
     der. The
	resulting range no longer has the heap property.

	1) Elements are compared using the given binary comparison function comp
     and
	projection object proj.
	2) Same as (1), but uses r as the range, as if using ranges::begin(r) as
     first and
	ranges::end(r) as last.

	The  function-like  entities  described on this page are niebloids, that
     is:

	  * Explicit template argument lists cannot be	specified  when  calling
     any of them.
	  * None of them are visible to argument-dependent lookup.
	  *  When any of them are found by normal unqualified lookup as the name
     to the left
	    of the function-call operator, argument-dependent lookup  is  inhib-
     ited.

	In  practice,  they may be implemented as function objects, or with spe-
     cial compiler
	extensions.

Parameters
	first, last - the range of elements to sort
	r	    - the range of elements to sort
	pred	    - predicate to apply to the projected elements
	proj	    - projection to apply to the elements

Return value
	An iterator equal to last.

Complexity
	Given  N  =  ranges::distance(first,  last),   at   most   \(\scriptsize
     2N\log{(N)}\)2Nlog(N)
	comparisons and \(\scriptsize 4N\log{(N)}\)4Nlog(N) projections.

Notes
	A  max heap is a range of elements [f, l), arranged with respect to com-
     parator comp
	and projection proj, that has the following properties:

	  * With N = l - f, p = f[(i - 1) / 2], and q = f[i], for all 0 < i < N,
     the
	    expression std::invoke(comp, std::invoke(proj, p), std::invoke(proj,
     q))
	    evaluates to false.
	  * A new element can be added using ranges::push_heap, in \(\scriptsize
	    \mathcal{O}(\log N)\)dh(log N) time.
	  *  The  first  element  can  be  removed  using  ranges::pop_heap,  in
     \(\scriptsize
	    \mathcal{O}(\log N)\)dh(log N) time.

Possible implementation
     struct sort_heap_fn {
	 template<std::random_access_iterator I, std::sentinel_for<I> S,
		  class Comp = ranges::less, class Proj = std::identity>
	 requires std::sortable<I, Comp, Proj>
	 constexpr I
	     operator()(I first, S last, Comp comp = {}, Proj proj = {}) const
	 {
	     auto ret {ranges::next(first, last)};
	     for (; first != last; --last)
		 ranges::pop_heap(first, last, comp, proj);
	     return ret;
	 }

	 template<ranges::random_access_range R, class Comp = ranges::less,
		  class Proj = std::identity>
	 requires std::sortable<ranges::iterator_t<R>, Comp, Proj>
	 constexpr ranges::borrowed_iterator_t<R>
	     operator()(R&& r, Comp comp = {}, Proj proj = {}) const
	 {
	     return  (*this)(ranges::begin(r),	ranges::end(r), std::move(comp),
     std::move(proj));
	 } };

     inline constexpr sort_heap_fn sort_heap {};

Example
     // Run this code

      #include <algorithm>
      #include <array>
      #include <iostream>

      void print(auto const& rem, auto const& v)
      {
	  std::cout << rem;
	  for (const auto i : v)
	      std::cout << i << ' ';
	  std::cout << '\n';
      }

      int main()
      {
	  std::array v {3, 1, 4, 1, 5, 9};
	  print("original array:  ", v);

	  std::ranges::make_heap(v);
	  print("after make_heap: ", v);

	  std::ranges::sort_heap(v);
	  print("after sort_heap: ", v);
      }

Output:
      original array:  3 1 4 1 5 9
      after make_heap: 9 5 4 1 1 3
      after sort_heap: 1 1 3 4 5 9

See also
	ranges::is_heap       checks if the given range is a max heap
	(C++20) 	      (niebloid)
	ranges::is_heap_until finds the largest subrange that is a max heap
	(C++20) 	      (niebloid)
	ranges::make_heap     creates a max heap out of a range of elements
	(C++20) 	      (niebloid)
	ranges::pop_heap      removes the largest element from a max heap
	(C++20) 	      (niebloid)
	ranges::push_heap     adds an element to a max heap
	(C++20) 	      (niebloid)
			      turns a max heap into a range of	elements  sorted
     in ascending
	sort_heap	      order
			      (function template)

http://cppreference.com 	   2024.06.10	       std::ranges::sort_heap(3)
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