12.rb

# part 1
x = y = deg = 0
data.lines.each do |s|
  d = s[1..].to_i
  case s[0]
  when 'N' then y += d
  when 'S' then y -= d
  when 'E' then x += d
  when 'W' then x -= d
  when 'L' then deg += d
  when 'R' then deg -= d
  when 'F'
    case deg % 360
    when 0 then x += d
    when 90 then y += d
    when 180 then x -= d
    when 270 then y -= d
    end
  end
end
p x.abs + y.abs

# part 2
sx = sy = 0
wx, wy = 10, 1
data.lines.each do |s|
  d = s[1..].to_i
  case s[0]
  when 'N' then wy += d
  when 'S' then wy -= d
  when 'E' then wx += d
  when 'W' then wx -= d
  when 'L' then (d / 90).times { wx, wy = -wy, wx }
  when 'R' then (d / 90).times { wx, wy = wy, -wx }
  when 'F' then sx += wx * d; sy += wy * d
  end
end
puts sx.abs + sy.abs