Another update from ingydotnet^djgoku

Task/Hailstone-sequence/Elixir/hailstone-sequence.elixir

@@ -1,21 +1,22 @@
 defmodule Hailstone do
-  def step(1), do: 0
-  def step(n) when Integer.even?(n), do: div(n,2)
-  def step(n) when Integer.odd?(n), do: n*3 + 1
+  require Integer
+
+  def step(1)                        , do: 0
+  def step(n) when Integer.is_even(n), do: div(n,2)
+  def step(n)                        , do: n*3 + 1
+
   def sequence(n) do
-    Enum.to_list(Stream.take_while(Stream.iterate(n, &step/1), &(&1 > 0)))
+    Stream.iterate(n, &step/1) |> Stream.take_while(&(&1 > 0)) |> Enum.to_list
   end
 
   def run do
-    seq27 = Hailstone.sequence(27)
+    seq27 = sequence(27)
     len27 = length(seq27)
-    repr = String.replace(inspect(seq27, limit: 4), "]",
-                          String.replace(inspect(Enum.drop(seq27,len27-4)), "[", ", "))
-    IO.puts("Hailstone(27) has #{len27} elements: #{repr}")
+    repr = String.replace(inspect(seq27, limit: 4) <> inspect(Enum.drop(seq27,len27-4)), "][", ", ")
+    IO.puts "Hailstone(27) has #{len27} elements: #{repr}"
 
-    {start, len}  = Enum.max_by( Enum.map(1..100_000, fn(n) -> {n, length(Hailstone.sequence(n))} end),
-                                 fn({_,len}) -> len end )
-    IO.puts("Longest sequence starting under 100000 begins with #{start} and has #{len} elements.")
+    {len, start} = Enum.map(1..100_000, fn(n) -> {length(sequence(n)), n} end) |> Enum.max
+    IO.puts "Longest sequence starting under 100000 begins with #{start} and has #{len} elements."
   end
 end