Day 6 - Advent of Code 2015

Mix.install([
  :kino,
  {:nx, "~> 0.4"}
])

:ok

Links

• Advent of Code (AoC)
• AoC Puzzle Input
• tylerj GitHub

Prompt

— Day 6: Probably a Fire Hazard —

Because your neighbors keep defeating you in the holiday house decorating contest year after year, you’ve decided to deploy one million lights in a 1000x1000 grid.

Furthermore, because you’ve been especially nice this year, Santa has mailed you instructions on how to display the ideal lighting configuration.

Lights in your grid are numbered from 0 to 999 in each direction; the lights at each corner are at 0,0, 0,999, 999,999, and 999,0. The instructions include whether to turn on, turn off, or toggle various inclusive ranges given as coordinate pairs. Each coordinate pair represents opposite corners of a rectangle, inclusive; a coordinate pair like 0,0 through 2,2 therefore refers to 9 lights in a 3x3 square. The lights all start turned off.

To defeat your neighbors this year, all you have to do is set up your lights by doing the instructions Santa sent you in order.

For example:

• turn on 0,0 through 999,999 would turn on (or leave on) every light.
• toggle 0,0 through 999,0 would toggle the first line of 1000 lights, turning off the ones that were on, and turning on the ones that were off.
• turn off 499,499 through 500,500 would turn off (or leave off) the middle four lights.

After following the instructions, how many lights are lit?

To begin, get your puzzle input.

— Part Two —

Part Two prompt

QUESTION TWO?

Although it hasn’t changed, you can still get your puzzle input.

Input

input = Kino.Input.textarea("Please paste your input file:")

input = input |> Kino.Input.read()

""

Solution

https://dockyard.com/blog/2022/07/12/elixir-versus-python-for-data-science https://dockyard.com/blog/2021/04/08/up-and-running-nx https://hexdocs.pm/nx/Nx.html#pad/3

t_new = Nx.broadcast(0, {1000, 1000})
# t1 = Nx.pad(
#   Nx.broadcast(1, {400, 400}),
#   0,
#   [
#     {200, 400, 0},
#     {200, 400, 0}
#   ]
# )

# Nx.bitwise_or(t_new, t1)

#Nx.Tensor<
  s64[1000][1000]
  [
    [0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, ...],
    ...
  ]
>

defmodule Day06 do
  defdelegate parse(input), to: __MODULE__.Input

  def part1(input) do
    input
    |> parse()
    |> Enum.map(& &1)
  end

  def part2(input) do
    input
    |> parse()
    |> Enum.map(& &1)
  end

  defmodule Input do
    def parse(input) when is_binary(input) do
      input
      |> String.split("\n")
      |> parse()
    end

    def parse(input) when is_list(input) do
      Stream.map(input, &parse_line/1)
    end

    def parse_line(line) do
      line
      # |> String.split(["-", ","])
      # |> Enum.map(&String.to_integer/1)
    end
  end
end

{:module, Day06, <<70, 79, 82, 49, 0, 0, 8, ...>>,
 {:module, Day06.Input, <<70, 79, 82, ...>>, {:parse_line, 1}}}

After following the instructions, how many lights are lit?

Your puzzle answer was answer one.

Day06.part1(input)

[""]

QUESTION TWO?

Your puzzle answer was answer two.

Day06.part2(input)

[""]

Both parts of this puzzle are complete! They provide two gold stars: **

At this point, you should return to your Advent calendar and try another puzzle.

If you still want to see it, you can get your puzzle input.

Benchmarking

defmodule Benchmark do
  def fun1(input) do
    Day06.part1(input)
  end

  def fun2(input) do
    Day06.part2(input)
  end
end

{:module, Benchmark, <<70, 79, 82, 49, 0, 0, 6, ...>>, {:fun2, 1}}

# https://github.com/bencheeorg/benchee
input = Day06.Input.parse(input) |> Enum.to_list()

Benchee.run(
  %{
    "fun1" => fn _ -> Benchmark.fun1(input) end,
    "fun2" => fn _ -> Benchmark.fun2(input) end
  },
  inputs: %{
    "Part 1" => 1
  },
  memory_time: 2,
  reduction_time: 2
)

nil

nil

Tests

ExUnit.start(auto_run: false)

defmodule Day06Test do
  use ExUnit.Case, async: false

  setup_all do
    [
      input: ""
    ]
  end

  describe "part1/1" do
    test "returns expected value", %{input: input} do
      assert Day06.part1(input) == [""]
    end
  end

  describe "part2/1" do
    test "returns expected value", %{input: input} do
      assert Day06.part2(input) == [""]
    end
  end
end

ExUnit.run()

..
Finished in 0.00 seconds (0.00s async, 0.00s sync)
2 tests, 0 failures

Randomized with seed 162351

%{excluded: 0, failures: 0, skipped: 0, total: 2}