Heapsort on top of Ruby's array

gistfile1.rb

class Array
	def heapsort!
		#heapify
		1.upto(self.length - 1) do |i|
			#move up
			child = i
			while child > 0
				parent = (child - 1) / 2
				if self[parent] < self[child]
					self[parent], self[child] = self[child], self[parent]
					child = parent
				else
					break
				end
			end
		end

		#sort
		i = self.length - 1
		while i > 0
			self[0], self[i] = self[i], self[0]
			i -= 1

			#move down
			parent = 0
			while parent * 2 + 1 <= i
				child = parent * 2 + 1
				if child < i && self[child] < self[child + 1]
					child += 1
				end
				if self[parent] < self[child]
					self[parent], self[child] = self[child], self[parent]
					parent = child
				else
					break
				end
			end
		end
	end
end



foo = [5, 11, 7, 2, 19, 4, 8, 22, 1, 12]
foo.heapsort!
p foo