42 lines
1.4 KiB
Elixir
42 lines
1.4 KiB
Elixir
defmodule DayDay21Part2 do
|
|
def run do
|
|
File.read!("input")
|
|
|> String.split("\n", trim: true)
|
|
|> Enum.map(&String.split(&1, [" (contains ", ", ", ")"], trim: true))
|
|
|> Enum.map(fn [ingredients | allergens] -> {String.split(ingredients), allergens} end)
|
|
|> Enum.reduce(%{}, fn {ingredients, allergens}, acc ->
|
|
ingredients = MapSet.new(ingredients)
|
|
|
|
Enum.reduce(allergens, acc, fn allergen, acc ->
|
|
Map.update(acc, allergen, ingredients, &MapSet.intersection(&1, ingredients))
|
|
end)
|
|
end)
|
|
|> Map.new(fn {allergen, ingredients} -> {allergen, MapSet.to_list(ingredients)} end)
|
|
|> resolve_ingredients([])
|
|
|> Enum.sort_by(fn {allergen, _ingredient} -> allergen end)
|
|
|> Enum.map(fn {_allergen, ingredient} -> ingredient end)
|
|
|> Enum.join(",")
|
|
|> IO.puts()
|
|
end
|
|
|
|
def resolve_ingredients(suspected, resolved) when map_size(suspected) == 0, do: resolved
|
|
|
|
def resolve_ingredients(suspected, resolved) do
|
|
{allergen, [ingredient]} =
|
|
Enum.find(suspected, fn {_allergen, ingredients} -> length(ingredients) == 1 end)
|
|
|
|
IO.puts("#{ingredient} contains #{allergen}")
|
|
|
|
suspected =
|
|
suspected
|
|
|> Map.delete(allergen)
|
|
|> Map.new(fn {allergen, ingredients} -> {allergen, ingredients -- [ingredient]} end)
|
|
|
|
resolved = [{allergen, ingredient} | resolved]
|
|
|
|
resolve_ingredients(suspected, resolved)
|
|
end
|
|
end
|
|
|
|
DayDay21Part2.run()
|