Move Zeroes -- Amazon Quesion

mv-zeroes.rb

#!/usr/bin/env ruby
# mv-zeroes
#
# Beware! Today's exercise, which derives from an interview question asked at
# Facebook, is trickier than it looks:
#
# You are given an array of integers. Write a program that moves all non-zero
# integers to the left end of the array, and all zeroes to the right end of the
# array. Your program should operate in place. The order of the non-zero
# integers doesn't matter. As an example, given the input array
# [1,0,2,0,0,3,4], your program should permute the array to [1,4,2,3,0,0,0] or
# something similar, and return the value 4.
#
# Your task is to write the indicated program. When you are finished, you are
# welcome to read or run a suggested solution, or to post your own solution or
# discuss the exercise in the comments below.

puts ARGF.read.split(' ').sort.reverse.join(' ')

mv-zeroes2.rb

#!/usr/bin/env ruby
# mv-zeroes2.rb
#
# Beware! Today's exercise, which derives from an interview question asked at
# Facebook, is trickier than it looks:
#
# You are given an array of integers. Write a program that moves all non-zero
# integers to the left end of the array, and all zeroes to the right end of the
# array. Your program should operate in place. The order of the non-zero
# integers doesn't matter. As an example, given the input array
# [1,0,2,0,0,3,4], your program should permute the array to [1,4,2,3,0,0,0] or
# something similar, and return the value 4.
#
# Let's assume we do care about ordering of the original non-zeroes:

class Array
  def move_zeroes()
    a = self
    x = y = 0
    l = a.length
    while x < l
      if a[x].to_i == 0
        x += 1
        next
      elsif y < x
        a[y] = a[x]
      end
      x += 1
      y += 1
    end
    while y < l
      a[y] = 0
      y += 1
    end
    a
  end
end

puts ARGF.read.split(' ').move_zeroes.join(' ')