ynonp

defmodule Day18 do
  def read_input do
    File.read!("input/day18.txt")
    |> String.split("\n", trim: true)
  end

  def solve_part2(expr) do
    cond do
      String.contains?(expr, "(") ->
        Regex.replace(~r/\(([^()]+)\)/, expr, fn _, expr -> solve_part2(expr) end)

ynonp

defmodule Day17 do
  def read_input do
    File.read!("input/day17.txt")
    |> String.split("\n", trim: true)
    |> Enum.map(&String.graphemes/1)
    |> Enum.map(&Enum.with_index/1)
    |> Enum.with_index
    |> Enum.flat_map(fn {line, row} -> Enum.map(line, fn {el, col} -> {{row, col, 0}, el } end) end)
    |> Enum.into(%{})
  end

ynonp

defmodule Day15 do
  def play(%{ :history => history, :last_value => value, :last_index => index }) do

    next_history = seen(history, value, index)
    next_value = get_value(next_history,  value)

    %{
      :history       => next_history,
      :last_index    => index + 1,
      :last_value    => next_value,

ynonp

defmodule VM14 do
  use Bitwise
  defstruct [:memory, :mask_bits_for_and, :mask_values_for_or]

  def new do
    %VM14{memory: %{}, mask_bits_for_and: 0, mask_values_for_or: 0, mask_str: "0"}
  end

  def update_mask(vm, mask_str) do
    mask_bits_for_and = mask_str

ynonp

defmodule Day13 do
  def read_input do
    [start_time, bus_times] = File.read!("input/day13.txt")
                              |> String.split("\n", trim: true)

    times = String.split(bus_times, ",", trim: true)
            |> Enum.reject(&(&1 == "x"))
            |> Enum.map(&String.to_integer/1)

    [String.to_integer(start_time), times]

ynonp

defmodule Ship do
  defstruct heading: 90, pos: { 0, 0 }

  def distance(ship) do
    Tuple.to_list(ship.pos)
    |> Enum.map(&(abs(&1)))
    |> Enum.sum
  end

  def move(ship, %{ "dir" => "L", "steps" => degrees}) do

ynonp

defmodule Day11 do
  def read_input do
    File.read!("input/day11.txt")
    |> String.split("\n", trim: true)
    |> Enum.map(&String.graphemes/1)
    |> Enum.map(&Enum.with_index/1)
    |> Enum.with_index
    |> Enum.flat_map(fn {line, row} -> Enum.map(line, fn {el, col} -> {{row, col}, el } end) end)
    |> Enum.into(%{})
  end

ynonp

defmodule Day10 do
  def read_input do
    File.read!("input/day10.txt")
    |> String.split("\n", trim: true)
    |> Enum.map(&String.to_integer/1)
    |> Enum.sort
  end

  def create_graph(lines) do
    nodes = [0] ++ lines ++ [Enum.max(lines) + 3]

ynonp

defmodule Day9 do
  @preamble_length 25

  def read_input do
    File.read!("input/day9.txt")
    |> String.split("\n", trim: true)
    |> Enum.map(&String.to_integer/1)
  end

  def valid?(window, item) do

ynonp

defmodule VM do
  defstruct [:ip, :code, :acc]
end

defmodule Day8 do
  def read_input do
    File.read!("input/day8.txt")
    |> String.split("\n", trim: true)
    |> Enum.map(&(String.split(&1, " ", trim: true)))
    |> Enum.map(fn [action, param] -> { action, String.to_integer(param) } end)