Advent of Code 2024 Day 11 Part 1

Mix.install([
  {:kino_aoc, "~> 0.1"}
])

Get Inputs

{:ok, puzzle_input} =
  KinoAOC.download_puzzle("2024", "11", System.fetch_env!("LB_SESSION"))

My answer

small_sample_input = "0 1 10 99 999"

stones =
  small_sample_input
  |> String.split(" ")
  |> Enum.map(&String.to_integer(&1))

blink = fn stone ->
  cond do
    stone == 0 ->
      [1]
    Integer.digits(stone) |> length() |> rem(2) == 0 ->
      digits = Integer.digits(stone)
      half_size = digits |> length() |> div(2)
      [
        digits |> Enum.slice(0, half_size) |> Integer.undigits(),
        digits |> Enum.slice(half_size, half_size) |> Integer.undigits(),
      ]
    true ->
      [stone * 2024]
  end
end

Enum.flat_map(stones, fn stone -> blink.(stone) end)

stones =
  "125 17"
  |> String.split(" ")
  |> Enum.map(&String.to_integer(&1))

1..6
|> Enum.reduce(stones, fn _, acc_stones ->
  Enum.flat_map(acc_stones, fn stone -> blink.(stone) end)
  |> IO.inspect()
end)
|> length()

1..25
|> Enum.reduce(stones, fn _, acc_stones ->
  Enum.flat_map(acc_stones, fn stone -> blink.(stone) end)
end)
|> length()

stones =
  puzzle_input
  |> String.split(" ")
  |> Enum.map(&String.to_integer(&1))

1..25
|> Enum.reduce(stones, fn _, acc_stones ->
  Enum.flat_map(acc_stones, fn stone -> blink.(stone) end)
end)
|> length()