advent-of-code/2016/ruby/day_08.rb

class Screen
  attr_reader :width, :height, :pixels

  def initialize(width, height)
    @width, @height = width, height
    @pixels = Array.new(height) { Array.new(width, false) }
  end

  def to_s
    pixels.map {|row| row.map {|pixel| pixel ? ?# : ?. }.join }.join("\n")
  end

  def <<(instruction)
    case instruction
    when /rect (\d+)x(\d+)/
      $1.to_i.times do |x|
        $2.to_i.times do |y|
          pixels[y][x] = true
        end
      end
    when /rotate column x=(\d+) by (\d+)/
      col = pixels.map {|row| row[$1.to_i] }.rotate(-$2.to_i)
      pixels.each do |row|
        row[$1.to_i] = col.shift
      end
    when /rotate row y=(\d+) by (\d+)/
      row = pixels[$1.to_i].rotate(-$2.to_i)
      pixels[$1.to_i] = row
    end
  end
end

if __FILE__ == $0
  screen = Screen.new(50, 6)
  DATA.lines.each do |line|
    screen << line
  end

  puts screen
  puts screen.pixels.map {|row| row.count {|pixel| pixel }}.inject(:+)
end

require 'minitest'
# require 'minitest/autorun'

class TestScreen < Minitest::Test
  def test_screen
    screen = Screen.new(7, 3)
    assert_equal <<-PIXELS.chomp, screen.to_s
.......
.......
.......
    PIXELS

    screen << 'rect 3x2'
    assert_equal <<-PIXELS.chomp, screen.to_s
###....
###....
.......
    PIXELS

    screen << 'rotate column x=1 by 1'
    assert_equal <<-PIXELS.chomp, screen.to_s
#.#....
###....
.#.....
    PIXELS

    screen << 'rotate row y=0 by 4'
    assert_equal <<-PIXELS.chomp, screen.to_s
....#.#
###....
.#.....
    PIXELS

    screen << 'rotate column x=1 by 1'
    assert_equal <<-PIXELS.chomp, screen.to_s
.#..#.#
#.#....
.#.....
    PIXELS
  end
end

__END__
rect 1x1
rotate row y=0 by 20
rect 1x1
rotate row y=0 by 2
rect 1x1
rotate row y=0 by 3
rect 2x1
rotate row y=0 by 2
rect 1x1
rotate row y=0 by 3
rect 2x1
rotate row y=0 by 2
rect 1x1
rotate row y=0 by 4
rect 2x1
rotate row y=0 by 2
rect 1x1
rotate row y=0 by 2
rect 1x1
rotate row y=0 by 2
rect 1x1
rotate row y=0 by 3
rect 2x1
rotate row y=0 by 2
rect 1x1
rotate row y=0 by 5
rect 1x1
rotate row y=0 by 2
rect 1x1
rotate row y=0 by 6
rect 5x1
rotate row y=0 by 2
rect 1x3
rotate row y=2 by 8
rotate row y=0 by 8
rotate column x=0 by 1
rect 7x1
rotate row y=2 by 24
rotate row y=0 by 20
rotate column x=5 by 1
rotate column x=4 by 2
rotate column x=2 by 2
rotate column x=0 by 1
rect 7x1
rotate column x=34 by 2
rotate column x=22 by 1
rotate column x=15 by 1
rotate row y=2 by 18
rotate row y=0 by 12
rotate column x=8 by 2
rotate column x=7 by 1
rotate column x=5 by 2
rotate column x=2 by 1
rotate column x=0 by 1
rect 9x1
rotate row y=3 by 28
rotate row y=1 by 28
rotate row y=0 by 20
rotate column x=18 by 1
rotate column x=15 by 1
rotate column x=14 by 1
rotate column x=13 by 1
rotate column x=12 by 2
rotate column x=10 by 3
rotate column x=8 by 1
rotate column x=7 by 2
rotate column x=6 by 1
rotate column x=5 by 1
rotate column x=3 by 1
rotate column x=2 by 2
rotate column x=0 by 1
rect 19x1
rotate column x=34 by 2
rotate column x=24 by 1
rotate column x=23 by 1
rotate column x=14 by 1
rotate column x=9 by 2
rotate column x=4 by 2
rotate row y=3 by 5
rotate row y=2 by 3
rotate row y=1 by 7
rotate row y=0 by 5
rotate column x=0 by 2
rect 3x2
rotate column x=16 by 2
rotate row y=3 by 27
rotate row y=2 by 5
rotate row y=0 by 20
rotate column x=8 by 2
rotate column x=7 by 1
rotate column x=5 by 1
rotate column x=3 by 3
rotate column x=2 by 1
rotate column x=1 by 2
rotate column x=0 by 1
rect 9x1
rotate row y=4 by 42
rotate row y=3 by 40
rotate row y=1 by 30
rotate row y=0 by 40
rotate column x=37 by 2
rotate column x=36 by 3
rotate column x=35 by 1
rotate column x=33 by 1
rotate column x=32 by 1
rotate column x=31 by 3
rotate column x=30 by 1
rotate column x=28 by 1
rotate column x=27 by 1
rotate column x=25 by 1
rotate column x=23 by 3
rotate column x=22 by 1
rotate column x=21 by 1
rotate column x=20 by 1
rotate column x=18 by 1
rotate column x=17 by 1
rotate column x=16 by 3
rotate column x=15 by 1
rotate column x=13 by 1
rotate column x=12 by 1
rotate column x=11 by 2
rotate column x=10 by 1
rotate column x=8 by 1
rotate column x=7 by 2
rotate column x=5 by 1
rotate column x=3 by 3
rotate column x=2 by 1
rotate column x=1 by 1
rotate column x=0 by 1
rect 39x1
rotate column x=44 by 2
rotate column x=42 by 2
rotate column x=35 by 5
rotate column x=34 by 2
rotate column x=32 by 2
rotate column x=29 by 2
rotate column x=25 by 5
rotate column x=24 by 2
rotate column x=19 by 2
rotate column x=15 by 4
rotate column x=14 by 2
rotate column x=12 by 3
rotate column x=9 by 2
rotate column x=5 by 5
rotate column x=4 by 2
rotate row y=5 by 5
rotate row y=4 by 38
rotate row y=3 by 10
rotate row y=2 by 46
rotate row y=1 by 10
rotate column x=48 by 4
rotate column x=47 by 3
rotate column x=46 by 3
rotate column x=45 by 1
rotate column x=43 by 1
rotate column x=37 by 5
rotate column x=36 by 5
rotate column x=35 by 4
rotate column x=33 by 1
rotate column x=32 by 5
rotate column x=31 by 5
rotate column x=28 by 5
rotate column x=27 by 5
rotate column x=26 by 3
rotate column x=25 by 4
rotate column x=23 by 1
rotate column x=17 by 5
rotate column x=16 by 5
rotate column x=13 by 1
rotate column x=12 by 5
rotate column x=11 by 5
rotate column x=3 by 1
rotate column x=0 by 1