aoc2020day6.ex

defmodule Day6 do
  def read_input do
    File.read!("input/day6.txt")
    |> String.split("\n\n", trim: true)
  end

  def get_common_answers(str) do
    answers = String.split(str, "\n", trim: true)
              |> Enum.map(&String.graphemes/1)
              |> Enum.map(&(MapSet.new(&1)))
              |> Enum.reduce(&MapSet.intersection/2)
  end

  def part1 do
    read_input
    |> Enum.map(&(String.replace(&1, "\n", "")))
    |> Enum.map(&(MapSet.new(String.graphemes(&1))))
    |> Enum.map(&(Enum.count(&1)))
    |> Enum.sum
    |> IO.inspect
  end

  def part2 do
    read_input
    |> Enum.map(&get_common_answers/1)
    |> Enum.map(&(Enum.count(&1)))
    |> Enum.sum
    |> IO.inspect
  end
end