gistfile1.rb

class String
  def py_slice(start, step = 1)
    start.step(step < 0 ? 0 : self.length, step).map { |index| self[index] }
  end
end

input = ARGF.readlines

for i in Range.new(0,input.size).step(4)
  northLasers, conveyorBelt, southLasers = input[i,3]
  x = conveyorBelt.index('X')
  west = (northLasers.py_slice(x,-2) + southLasers.py_slice(x-1,-2)).count('|')
  east = (northLasers.py_slice(x, 2) + southLasers.py_slice(x+1, 2)).count('|')
  puts east < west ? "GO EAST" : "GO WEST"
end