Submission #20374218

---

Source Code Expand

defmodule Main do
  def main() do
    n = IO.read(:line) |> String.trim() |> String.to_integer()
    digits = Integer.to_string(n) |> String.codepoints() |> Enum.count()

    numbers(digits)
    |> Enum.filter(&(&1 <= n))
    |> Enum.count()
    |> IO.puts()
  end

  defp numbers(digits) do
    1..digits
    |> Enum.reduce([[]], fn _, list_of_lists ->
      Enum.reduce(list_of_lists, [], fn list, acc ->
        [[3 | list], [5 | list], [7 | list], list | acc]
      end)
    end)
    |> Enum.filter(fn list ->
      Enum.any?(list, &(&1 == 3)) and Enum.any?(list, &(&1 == 5)) and Enum.any?(list, &(&1 == 7))
    end)
    |> Enum.map(fn list ->
      Enum.join(list) |> String.to_integer()
    end)
    |> MapSet.new()
  end
end

Submission Info

Judge Result