2016 Update

Task/Sorting-algorithms-Heapsort/Elixir/sorting-algorithms-heapsort.elixir

@@ -0,0 +1,37 @@
+defmodule Sort do
+  def heapSort(list) do
+    len = length(list)
+    heapify(List.to_tuple(list), div(len - 2, 2))
+    |> heapSort(len-1)
+    |> Tuple.to_list
+  end
+
+  defp heapSort(a, finish) when finish > 0 do
+    swap(a, 0, finish)
+    |> siftDown(0, finish-1)
+    |> heapSort(finish-1)
+  end
+  defp heapSort(a, _), do: a
+
+  defp heapify(a, start) when start >= 0 do
+    siftDown(a, start, tuple_size(a)-1)
+    |> heapify(start-1)
+  end
+  defp heapify(a, _), do: a
+
+  defp siftDown(a, root, finish) when root * 2 + 1 <= finish do
+    child = root * 2 + 1
+    if child + 1 <= finish and elem(a,child) < elem(a,child + 1), do: child = child + 1
+    if elem(a,root) < elem(a,child),
+      do:   swap(a, root, child) |> siftDown(child, finish),
+      else: a
+  end
+  defp siftDown(a, _root, _finish), do: a
+
+  defp swap(a, i, j) do
+    {vi, vj} = {elem(a,i), elem(a,j)}
+    a |> put_elem(i, vj) |> put_elem(j, vi)
+  end
+end
+
+(for _ <- 1..20, do: :rand.uniform(20)) |> IO.inspect |> Sort.heapSort |> IO.inspect