func heapSort(arr []int) []int {
buildMaxHeap(arr, arrLen)
for i := arrLen - 1; i >= 0; i-- {
func buildMaxHeap(arr []int, arrLen int) {
for i := arrLen / 2; i >= 0; i-- {
func heapify(arr []int, i, arrLen int) {
if left < arrLen && arr[left] > arr[largest] {
if right < arrLen && arr[right] > arr[largest] {
heapify(arr, largest, arrLen)
func swap(arr []int, i, j int) {
arr[i], arr[j] = arr[j], arr[i]