Day 6

Mix.install([
  {:kino, "~> 0.6.2"}
])

Input

input = Kino.Input.textarea("Please dump your inputs")

Part 1

fish = Kino.Input.read(input) |> String.split(",", trim: true) |> Enum.map(&String.to_integer/1)

defmodule Lantern do
  def cycle(fish) do
    aged =
      for x <- 1..8 do
        {x - 1, Map.get(fish, x, 0)}
      end
      |> Enum.into(%{})

    Map.update(aged, 6, 0, &amp;(&amp;1 + Map.get(fish, 0, 0)))
    |> Map.put(8, Map.get(fish, 0, 0))
  end
end

fishmap =
  Enum.reduce(0..7, %{}, fn num, acc ->
    Map.put(acc, num, Enum.count(fish, &(&1 == num)))
  end)
  |> Enum.into(%{})

Enum.reduce(0..256, fishmap, fn x, fish ->
  IO.puts("Day #{x}, #{Enum.sum(Map.values(fish))} fish")
  Lantern.cycle(fish)
end)