anagram.exs

defmodule S do
  def anagram(xs, ys) do
    count(xs) == count(ys)
  end

  defp count(xs), do: count(xs, %{})
  defp count(<<>>, seen), do: seen
  defp count(<<x::utf8, rest::binary>>, seen) do
    count(rest, Map.put(seen, x, (seen[x] || 0) + 1))
  end

  def test do
    true = anagram("asdf", "fdsa")
    false = anagram("aaaa", "aaa")

    :ok
  end
end