Heap sort in Scala

heapsort

object heapsort {
  def left(i: Int) = (2*i) + 1                    //> left: (i: Int)Int
  def right(i: Int) = left(i) + 1                 //> right: (i: Int)Int
  def parent(i: Int) = (i - 1) / 2                //> parent: (i: Int)Int

	def swap(a: Array[Int], i: Int, j: Int): Unit = {
		val t = a(i)
		a(i) = a(j)
		a(j) = t
	}                                         //> swap: (a: Array[Int], i: Int, j: Int)Unit
	
	def maxHeap (a: Array[Int], i: Int, size: Int): Unit = {
		val l = left(i)
		val r = right(i)
		var m = -1
		m = if (l < size && a(l) > a(i)) {l} else {i}
		m = if (r < size && a(r) > a(m)) {r} else {m}
		if (m != i) {
			swap(a, i, m)
			maxHeap(a, m, size)
		}
	}                                         //> maxHeap: (a: Array[Int], i: Int, size: Int)Unit
	
	def buildMaxHeap (a: Array[Int], size: Int): Unit = {
		println(s"$a -> $size")
		val hs = size / 2
		for (i <- 0 to hs) {
			println(s"i -> $i")
			maxHeap(a, hs - i, size)
		}
	}                                         //> buildMaxHeap: (a: Array[Int], size: Int)Unit
	
	def heapSort (a: Array[Int]) {
		buildMaxHeap(a, a.length)
		for (i <- (0 until a.length).reverse) {
			swap(a, 0, i)
			maxHeap(a, 0, i)
		}
	}                                         
	
	val data = Array (1,0,2,9,3,8,4,7,5,6)
	heapSort (data)
	data
}