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