def heapsort(arr):
""" Implements heapsort
O(n*log(n))
"""
heap = Heap(arr)
for i in range(heap.size - 1, 0, -1):
heap.heap[0], heap.heap[heap.size - 1] = heap.heap[heap.size -
1], heap.heap[0]
heap.size -= 1
heap.max_heapify(0)
return heap.heap # Ordered array
