Advent of Code 2022 - Day 03

Mix.install([
  {:kino, "~> 0.7.0"}
])

Setup

example_input = """
vJrwpWtwJgWrhcsFMMfFFhFp
jqHRNqRjqzjGDLGLrsFMfFZSrLrFZsSL
PmmdzqPrVvPwwTWBwg
wMqvLMZHhHMvwLHjbvcjnnSBnvTQFn
ttgJtRGJQctTZtZT
CrZsJsPPZsGzwwsLwLmpwMDw
"""

input = Kino.Input.textarea("Puzzle Input", default: example_input)

Part 1

item_values =
  [?a..?z, ?A..?Z]
  |> Enum.concat()
  |> Enum.with_index(1)
  |> Map.new(fn {char, value} -> {<>, value} end)

input
|> Kino.Input.read()
|> String.split("\n", trim: true)
|> Enum.flat_map(fn rustsack ->
  {first_compartment, second_compartment} =
    rustsack
    |> String.graphemes()
    |> Enum.split(div(String.length(rustsack), 2))

  first_compartment
  |> MapSet.new()
  |> MapSet.intersection(MapSet.new(second_compartment))
end)
|> Enum.map(&amp;Map.fetch!(item_values, &amp;1))
|> Enum.sum()

Part 2

input
|> Kino.Input.read()
|> String.split("\n")
|> Enum.chunk_every(3)
|> Enum.flat_map(fn group ->
  group
  |> Enum.map(fn rustsack ->
    rustsack
    |> String.graphemes()
    |> MapSet.new()
  end)
  |> Enum.reduce(&MapSet.intersection/2)
end)
|> Enum.map(&Map.fetch!(item_values, &1))
|> Enum.sum()