advent8

advent8.rb

text=File.open('8.txt').read


m = [
  Array.new(50,0),
  Array.new(50,0),
  Array.new(50,0),
  Array.new(50,0),
  Array.new(50,0),
  Array.new(50,0),
]

def rect(m, line)
  x,y = (%r|rect (\d+)x(\d+)|).match(line)[1,2]
  (0..(y.to_i - 1)).each do |i|
    (0..(x.to_i - 1)).each do |j|
      m[i][j] = 1
    end
  end
end

def rotate_row(m, line)
  y, n = (%r|rotate row y=(\d+) by (\d+)|).match(line)[1,2]
  y = y.to_i
  n = n.to_i

  row = m[y]
  i = -1
  m[y] = row.map {|v| i += 1; row[(i-n)%row.size]}
end

def rotate_column(m, line)
  x, n = (%r|rotate column x=(\d+) by (\d+)|).match(line)[1,2]
  x = x.to_i
  n = n.to_i

  i = -1
  new_values = (0..m.size).map do
    i += 1
    m[(i-n)%m.size][x]
  end
  (0..(m.size - 1)).each do |i|
    m[i][x] = new_values[i]
  end
end

text.lines.each do |line|
  rect(m, line)if line.include?('rect')
  rotate_row(m, line) if line.include?('rotate row')
  rotate_column(m, line) if line.include?('rotate column')

  m.each do |y|
    puts y.map{|c| c == 0 ? ' ' : '▩'}.join('')
  end

  puts "=================="
end

puts m.inject(0){|agg, row| agg+row.inject(0,&:+) }