40 lines
889 B
Elixir
40 lines
889 B
Elixir
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defmodule AOC.Day3 do
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use AOC.Day, day: 3
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def parse_input(lines), do: lines
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def part1(input) do
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input
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|> Enum.map(fn line ->
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comp_size = line |> String.length() |> div(2)
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{comp1, comp2} = line |> String.to_charlist() |> Enum.split(comp_size)
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comp1 = MapSet.new(comp1)
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comp2 = MapSet.new(comp2)
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MapSet.intersection(comp1, comp2)
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|> MapSet.to_list()
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|> hd()
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|> get_priority()
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end)
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|> Enum.sum()
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end
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def part2(input) do
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input
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|> Enum.chunk_every(3)
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|> Enum.map(fn group ->
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group
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|> Enum.map(&String.to_charlist/1)
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|> Enum.map(&MapSet.new/1)
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|> Enum.reduce(&MapSet.intersection/2)
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|> MapSet.to_list()
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|> hd()
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|> get_priority()
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end)
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|> Enum.sum()
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end
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def get_priority(char) when char >= ?a, do: char - 96
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def get_priority(char), do: char - 38
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end
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