Heapsort, because I haven’t posted in a while

This is heapsort in a Swift playground. I needed a stable sort, so naturally I wrote an… unstable sort.

Of course, you can just use sort() or sorted(), but if you are inclined to roll your own, the Swifty way to do it is to create an extension. Note that an Array extension with a Generic Where Clause is needed to make element comparisons > < == work.

On to writing mergesort (stable).