### Heap Sort Algorithm in Kotlin

In this tutorial, we will write a Program to implement the Heap Sort algorithm in Kotlin programming language.

Heap sort is a comparison-based sorting technique based on the Binary Heap data structure. It is similar to the selection sort where we first find the minimum element and place the minimum element at the beginning. We repeat the same process for the remaining elements.

# Heap Sort Algorithm in Kotlin

Let's write the Kotlin program to implement the Heap sort algorithm to sort an array of elements in ascending order:
``````import java.util.*

fun <E: Comparable<E>> Array<E>.sort() {
val middle = size / 2 - 1
for (i in middle downTo 0) {
heapify(this, size, i)
}
for (i in size - 1 downTo 0) {
this[0] = this[i].also { this[i] = this[0] }
heapify(this, i, 0)
}
}

private fun <E: Comparable<E>> heapify(arr: Array<E>, heapSize: Int, root: Int) {
var largest = root
val leftNode = 2 * root + 1
val rightNode = 2 * root + 2
if (leftNode < heapSize && arr[leftNode] > arr[largest]) largest = leftNode
if (rightNode < heapSize && arr[rightNode] > arr[largest]) largest = rightNode

if (largest != root) {
arr[root] = arr[largest].also { arr[largest] = arr[root] }
heapify(arr, heapSize, largest)
}
}

fun main(args: Array<String>) {
val nums = arrayOf(2, 12, 89, 23, 76, 43, 12)
nums.sort()
println(Arrays.toString(nums))

val languages = arrayOf("Kotlin", "Java", "C#", "R", "Python", "Scala", "Groovy", "C", "C++")
languages.sort()
println(Arrays.toString(languages))
}
``````

Output:

``````[2, 12, 12, 23, 43, 76, 89]
[C, C#, C++, Groovy, Java, Kotlin, Python, R, Scala]``````