Data commit

Task/Smith-numbers/Elixir/smith-numbers.elixir

@@ -0,0 +1,21 @@
+defmodule Smith do
+  def number?(n) do
+    d = decomposition(n)
+    length(d)>1 and sum_digits(n) == Enum.map(d, &sum_digits/1) |> Enum.sum
+  end
+
+  defp sum_digits(n) do
+    Integer.digits(n) |> Enum.sum
+  end
+
+  defp decomposition(n, k\\2, acc\\[])
+  defp decomposition(n, k, acc) when n < k*k, do: [n | acc]
+  defp decomposition(n, k, acc) when rem(n, k) == 0, do: decomposition(div(n, k), k, [k | acc])
+  defp decomposition(n, k, acc), do: decomposition(n, k+1, acc)
+end
+
+m = 10000
+smith = Enum.filter(1..m, &Smith.number?/1)
+IO.puts "#{length(smith)} smith numbers below #{m}:"
+IO.puts "First 10: #{Enum.take(smith,10) |> Enum.join(", ")}"
+IO.puts "Last  10: #{Enum.take(smith,-10) |> Enum.join(", ")}"