test_gc.exs

defmodule Test do

  def question_1(), do: question_1(100_000_000)
  def question_1(num), do: question_1(num, rem(num, 1119))
  def question_1(num, 0), do: num
  def question_1(num, _), do: question_1(num+1)

  def question_2(num) do
    num
    |> Integer.to_string()
    |> String.split("", trim: true)
  end

  def question_3(charlist), do: question_3(charlist, %{})
  def question_3([], res), do: res
  def question_3([char|tail], res), do: question_3(tail, Map.update(res, char, 1, & &1+1))
  
end

answer_1 = Test.question_1()
IO.puts(answer_1)
answer_2 = Test.question_2(answer_1)
IO.inspect(answer_2)
answer_3 = Test.question_3(answer_2)
IO.inspect(answer_3)


### Result on console:
# 100000554
# ["1", "0", "0", "0", "0", "0", "5", "5", "4"]
# %{"0" => 5, "1" => 1, "4" => 1, "5" => 2}