Add Elixir example for selection sort

spadarjauhien · egonSchiele · commit fa35ae875d94 · 2018-04-20T08:18:52.000-07:00
diff --git a/02_selection_sort/elixir/01_selection_sort.exs b/02_selection_sort/elixir/01_selection_sort.exs
@@ -0,0 +1,24 @@
+defmodule SelectionSort do
+  def sort(list), do: do_sort(list, [])
+
+  defp do_sort([], acc), do: Enum.reverse(acc)
+
+  defp do_sort(list, acc) do
+    smallest_index = find_smallest_index(list, 0, nil, nil)
+    {smallest_value, list_rest} = List.pop_at(list, smallest_index)
+    do_sort(list_rest, [smallest_value | acc])
+  end
+
+  defguardp new_smallest_value?(value, min_value) when is_nil(min_value) or value < min_value
+
+  defp find_smallest_index([], _, _, min_index), do: min_index
+
+  defp find_smallest_index([head | tail], index, min_value, _)
+       when new_smallest_value?(head, min_value),
+       do: find_smallest_index(tail, index + 1, head, index)
+
+  defp find_smallest_index([_ | tail], index, min_value, min_index),
+    do: find_smallest_index(tail, index + 1, min_value, min_index)
+end
+
+IO.inspect(SelectionSort.sort([5, 3, 6, 2, 10]))
