defmodule Aoc2023.Day6 do
  use Aoc2023

  def parse(input) do
    input
    |> lines
    |> Enum.map(pipe(
      String.split(":")
      |> Enum.at(1)
    ))
  end

  def part1(input) do
    input
    |> Enum.map(pipe(
      String.split()
      |> Enum.map(&String.to_integer/1)
    ))
    |> Enum.zip()
    |> Enum.map(fn {time, dist} ->
      1..time
      |> Enum.map(&(&1 * (time - &1)))
      |> Enum.filter(&(&1 > dist))
      |> length
    end)
    |> Enum.product()
  end

  def part2(input) do
    [time, dist] = input
    |> Enum.map(pipe(String.replace(~r(\s+), "") |> String.to_integer()))
    1..(time)
    |> Stream.map(&(&1 * (time - &1)))
    |> Stream.filter(&(&1 > dist))
    |> Enum.count
  end
end