48 lines
836 B
Elixir
48 lines
836 B
Elixir
defmodule Day5 do
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def input() do
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File.stream!("input/day5.in")
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|> Stream.map(&String.trim/1)
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|> Enum.at(0)
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end
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def part1() do
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input()
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|> String.graphemes()
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|> react()
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|> Enum.count()
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end
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def part2() do
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for(n <- ?a..?z, do: <<n::utf8>>)
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|> Enum.map(fn c ->
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input()
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|> String.replace(c, "")
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|> String.replace(String.upcase(c), "")
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|> String.graphemes()
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|> react()
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end)
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|> Enum.min_by(&Enum.count/1)
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|> Enum.count()
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end
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def react(polymer) do
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Enum.reduce(polymer, [], fn
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x, [] ->
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[x]
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x, [y] ->
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[x, y]
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x, [y | ys] ->
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if x != y && String.downcase(x) == String.downcase(y) do
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ys
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else
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[x, y | ys]
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end
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end)
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end
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end
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IO.puts(Day5.part1())
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IO.puts(Day5.part2())
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