sasa1977

# This is the proper BEAM test for https://github.com/uber/denial-by-dns. The Erlang test in that repo is sequential
# (https://github.com/uber/denial-by-dns/blob/b809cc561a691d9d6201d06d38d06c33c9c9f9ec/erlang-httpc/main.erl)
# which is not consistent with the test description (https://github.com/uber/denial-by-dns/tree/b809cc561a691d9d6201d06d38d06c33c9c9f9ec#how-it-works)
# and also differs from e.g. go test in the same repo which issues requests concurrently.
#
# Consequently, the conclusion in that repo as well as the original article (https://eng.uber.com/denial-by-dns/) is incorrect.
# A properly written Erlang test would pass, as demonstrated by this Elixir script.
#
# This code performs a slightly refined and a correct version of that tests in Elixir:
#

sasa1977

defmodule SqlParser do
  def run() do
    input = "select col1 from (
      select col2, col3 from (
        select col4, col5, col6 from some_table
      )
    )
    "
    IO.puts("input: #{inspect(input)}\n")
    IO.inspect(parse(input))

sasa1977

defmodule Day25 do
  def part1(), do:
    input()
    |> run_machine()
    |> tape()
    |> Stream.filter(&match?({_pos, 1}, &1))
    |> Enum.count()

  defp run_machine(input), do:
    Enum.reduce(

sasa1977

defmodule Day24 do
  def part1(), do:
    connections() |> all_bridges() |> Stream.map(&(&1.strength)) |> Enum.max()

  def part2(), do:
    (connections() |> all_bridges() |> Enum.max_by(&{&1.length, &1.strength})).strength

  defp all_bridges(connections), do:
    Enum.reduce(Map.get(connections, 0), [], &bridges(connections, {0, &1}, &2))

sasa1977

defmodule Day23 do
  defmodule Machine.Core do
    def new(instructions), do:
      %{
        registers: %{},
        position: 0,
        instructions: instructions |> Enum.to_list() |> :array.from_list(fixed: true)
      }

    def done?(machine), do:

sasa1977

defmodule Day22 do
  def part1(), do:
    count_infected(10_000, [:clean, :infected])

  def part2(), do:
    count_infected(10_000_000, [:clean, :weakened, :infected, :flagged])

  defp count_infected(num_moves, state_transitions), do:
    state_transitions |> new_virus() |> count_infected(num_moves, 0)

sasa1977

defmodule Day21 do
  def part1(), do:
    enhancements() |> generate_art(5) |> count_pixels()

  def part2(), do:
    enhancements() |> generate_art(18) |> count_pixels()

  defp count_pixels(grid), do:
    Enum.count(for <<bit::1 <- grid>>, bit == 1, do: bit)

sasa1977

defmodule Day20 do
  def part1() do
    {id, _particle} = Enum.min_by(particles(), &particle_weight/1)
    id
  end

  def part2() do
    particles = particles()
    count_survivors(particles, sorted_collisions(particles))
  end

sasa1977

defmodule Day19 do
  def part1(), do:
    read_map() |> trip_steps() |> encountered_letters() |> Enum.to_list()

  def part2(), do:
    read_map() |> trip_steps() |> Enum.count()

  defp encountered_letters(trip_steps), do:
    trip_steps |> Stream.map(&Map.fetch!(&1.map, &1.pos)) |> Stream.reject(&(&1 in [?|, ?-, ?+]))

sasa1977

defmodule Day18 do
  defmodule Machine.Core do
    def new(instructions), do:
      %{
        registers: %{},
        position: 0,
        instructions: instructions |> Enum.to_list() |> :array.from_list(fixed: true)
      }

    def done?(machine), do: