Approach

Algorithm

With a Max Heap, the largest element is immediately available at index 0 without extra searching. This makes it easy to place the largest element at the end of the array.
If the goal is to sort the array in descending order, the maximum element needs to be extracted first. A Max Heap allows us to extract the maximum element efficiently in O(log n) time.
If the goal were to sort the array in ascending order, a Min Heap would be used instead. The Min Heap ensures the smallest element is at the root and can be easily moved to its correct position.

Rearrange the elements of the array and build a max-heap.
Start iterating with the whole array being unsorted initially.
Swap the element at index 0 (the largest) with the element at the last position in the unsorted portion of the array. The largest element is now at the end, in its correct sorted position.
Reduce the size of the unsorted portion of the array by one from the back (since the very last element is now sorted).
Re-heapify from the top (index 0) downwards to restore the Max Heap property for the remaining unsorted portion (the sorted portion of the array must be kept undisturbed).