2016 Update

Task/Order-disjoint-list-items/Elixir/order-disjoint-list-items.elixir

@@ -0,0 +1,39 @@
+defmodule Order do
+  def disjoint(m,n) do
+    IO.write "#{Enum.join(m," ")} | #{Enum.join(n," ")} -> "
+    Enum.chunk(n,2)
+    |> Enum.reduce({m,0}, fn [x,y],{m,from} ->
+         md = Enum.drop(m, from)
+         if x > y and x in md and y in md do
+           if Enum.find_index(md,&(&1==x)) > Enum.find_index(md,&(&1==y)) do
+             new_from = max(Enum.find_index(m,&(&1==x)), Enum.find_index(m,&(&1==y))) + 1
+             m = swap(m,from,x,y)
+             from = new_from
+           end
+         end
+         {m,from}
+       end)
+    |> elem(0)
+    |> Enum.join(" ")
+    |> IO.puts
+  end
+
+  defp swap(m,from,x,y) do
+    ix = Enum.find_index(m,&(&1==x)) + from
+    iy = Enum.find_index(m,&(&1==y)) + from
+    vx = Enum.at(m,ix)
+    vy = Enum.at(m,iy)
+    m |> List.replace_at(ix,vy) |> List.replace_at(iy,vx)
+  end
+end
+
+[ {"the cat sat on the mat", "mat cat"},
+  {"the cat sat on the mat", "cat mat"},
+  {"A B C A B C A B C"     , "C A C A"},
+  {"A B C A B D A B E"     , "E A D A"},
+  {"A B"                   , "B"},
+  {"A B"                   , "B A"},
+  {"A B B A"               , "B A"}     ]
+|> Enum.each(fn {m,n} ->
+     Order.disjoint(String.split(m),String.split(n))
+   end)