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