107 lines
2.2 KiB
Elixir
107 lines
2.2 KiB
Elixir
defmodule Day4 do
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defp read_input do
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Path.expand('input', Path.dirname(__ENV__.file))
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|> File.read!()
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end
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defp parse_passports(text) do
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String.split(text, "\n\n")
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|> Enum.map(fn block ->
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fields = String.split(block)
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Enum.reduce(fields, %{}, fn field, passport ->
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[key, val] = String.split(field, ":")
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Map.put(passport, key, val)
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end)
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end)
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end
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@required_fields [
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"byr",
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"iyr",
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"eyr",
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"hgt",
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"hcl",
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"ecl",
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"pid"
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# "cid"
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]
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defp all_fields?(passport) do
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Enum.all?(@required_fields, fn field ->
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case Map.fetch(passport, field) do
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{:ok, _val} -> true
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:error -> false
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end
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end)
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end
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defp parse_int(val, default) do
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try do
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String.to_integer(val)
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rescue
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ArgumentError -> default
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end
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end
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defp valid?(passport) do
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validators = %{
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"byr" => fn val ->
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int = parse_int(val, 0)
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1920 <= int && int <= 2002
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end,
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"iyr" => fn val ->
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int = parse_int(val, 0)
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2010 <= int && int <= 2020
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end,
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"eyr" => fn val ->
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int = parse_int(val, 0)
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2020 <= int && int <= 2030
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end,
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"hgt" => fn val ->
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case Regex.named_captures(~r/^(?<num>\d+)(?<units>cm|in)$/, val) do
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%{"num" => num, "units" => units} ->
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int = parse_int(num, 0)
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case units do
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"cm" ->
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150 <= int && int <= 193
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"in" ->
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59 <= int && int <= 76
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end
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_ ->
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false
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end
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end,
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"hcl" => fn val -> Regex.match?(~r/^#[0-9a-f]{6}$/, val) end,
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"ecl" => fn val -> Enum.member?(["amb", "blu", "brn", "gry", "grn", "hzl", "oth"], val) end,
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"pid" => fn val -> Regex.match?(~r/^[0-9]{9}$/, val) end
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# cid
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}
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Map.to_list(validators)
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|> Enum.all?(fn {field, validator} ->
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case Map.get(passport, field) do
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nil -> false
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val -> validator.(val)
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end
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end)
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end
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def part1 do
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read_input()
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|> parse_passports()
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|> Enum.count(&all_fields?/1)
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end
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def part2 do
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read_input()
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|> parse_passports()
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|> Enum.count(&valid?/1)
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end
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end
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Day4.part1() |> IO.inspect()
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Day4.part2() |> IO.inspect()
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