Day 06

Mix.install([
  {:kino, "~> 0.14.2"}
])

IEx.Helpers.c("/Users/johnb/dev/2015adventOfCode/advent_of_code.ex")
alias AdventOfCode, as: AOC
alias Kino.Input
require Integer

# Note: when making the next template, something like this works well:
#   `cat day01.livemd | sed 's/01/02/' > day02.livemd`
#

Installation and Data

input_p1example = Kino.Input.textarea("Example Data")

input_p1puzzleInput = Kino.Input.textarea("Puzzle Input")

input_source_select =
  Kino.Input.select("Source", [{:example, "example"}, {:puzzle_input, "puzzle input"}])

p1data = fn ->
  (Kino.Input.read(input_source_select) == :example &&
     Kino.Input.read(input_p1example)) ||
    Kino.Input.read(input_p1puzzleInput)
end

Part 1

defmodule Day06 do
  @p1_grid_size 1000
  def solve1(text) do
    text
    |> AOC.as_single_lines()
    |> Enum.reduce(MapSet.new(), fn line, set ->
      [[_, x1, y1, x2, y2]] = Regex.scan(~r/(\d+),(\d+) through (\d+),(\d+)/, line)
      [x1, y1, x2, y2] = Enum.map([x1, y1, x2, y2], fn n -> String.to_integer(n) end)
      rectangle = for x <- x1..x2, y <- y1..y2 do 
          x * @p1_grid_size + y 
        end
        |> MapSet.new()
        # |> IO.inspect()
      cond do
        line =~ "turn on" -> 
          MapSet.union(set, rectangle)
        line =~ "turn off" -> 
          Enum.reduce(rectangle, set, fn item, acc -> MapSet.delete(acc, item) end)
        line =~ "toggle" ->
          Enum.reduce(rectangle, set, fn item, acc ->
            if MapSet.member?(acc, item) do
              MapSet.delete(acc, item)
            else
              MapSet.put(acc, item)
            end
          end)
      end
      # |> IO.inspect()
    end)
    |> Enum.count()
  end

  def solve2(text) do
    text
    |> AOC.as_single_lines()
    |> Enum.reduce(%{}, fn line, set ->
      [[_, x1, y1, x2, y2]] = Regex.scan(~r/(\d+),(\d+) through (\d+),(\d+)/, line)
      [x1, y1, x2, y2] = Enum.map([x1, y1, x2, y2], fn n -> String.to_integer(n) end)
      rectangle = for x <- x1..x2, y <- y1..y2 do 
          x * @p1_grid_size + y 
        end
      cond do
        line =~ "turn on" -> 
          Enum.reduce(rectangle, set, fn item, acc ->
            Map.put(acc, item, (acc[item] || 0) + 1)
          end)
        line =~ "turn off" -> 
          Enum.reduce(rectangle, set, fn item, acc ->
            if (acc[item] || 0) > 1 do
              Map.put(acc, item, acc[item] - 1)
            else
              Map.delete(acc, item)
            end
          end)
        line =~ "toggle" ->
          Enum.reduce(rectangle, set, fn item, acc ->
            Map.put(acc, item, (acc[item] || 0) + 2)
          end)
      end
      # |> IO.inspect()
    end)
    |> Map.values()
    |> Enum.sum()
  end
end

# Example data:
# turn on 4,5 through 5,9 (10 lights on brightness = 10)
# turn off 3,3 through 4,8 (12 but only removes 4 brightness = 6)
# turn off 4,8 through 8,9 (10 but only removes 3 brightness = 3)
# toggle 5,9 through 8,9 (4 but only turns on 4 more with 2x more brightness = 19)
# 19

# p1data.()
# |> Day06.solve1()
# |> IO.inspect(label: "\n*** Part 1 solution (example: 7)")
# 543903

p1data.()
|> Day06.solve2()
|> IO.inspect(label: "\n*** Part 2 solution (example: 11)")
# 14687245