Merge pull request tarunsinghofficial#748 from thesmitpatel/patch-1

Create heap_sort.py

python-programming-2/heap_sort.py

@@ -0,0 +1,43 @@
+def heapify(nums, heap_size, root_index):
+ # Assume the index of the largest element is the root index
+ largest = root_index
+ left_child = (2 * root_index) + 1
+ right_child = (2 * root_index) + 2
+
+ # If the left child of the root is a valid index, and the element is greater
+ # than the current largest element, then update the largest element
+ if left_child < heap_size and nums[left_child] > nums[largest]:
+ largest = left_child
+
+ # Do the same for the right child of the root
+ if right_child < heap_size and nums[right_child] > nums[largest]:
+ largest = right_child
+
+ # If the largest element is no longer the root element, swap them
+ if largest != root_index:
+ nums[root_index], nums[largest] = nums[largest], nums[root_index]
+ # Heapify the new root element to ensure it's the largest
+ heapify(nums, heap_size, largest)
+
+
+def heap_sort(nums):
+ n = len(nums)
+
+ # Create a Max Heap from the list
+ # The 2nd argument of range means we stop at the element before -1 i.e.
+ # the first element of the list.
+ # The 3rd argument of range means we iterate backwards, reducing the count
+ # of i by 1
+ for i in range(n, -1, -1):
+ heapify(nums, n, i)
+
+ # Move the root of the max heap to the end of
+ for i in range(n - 1, 0, -1):
+ nums[i], nums[0] = nums[0], nums[i]
+ heapify(nums, i, 0)
+
+
+# Verify it works
+random_list_of_nums = [35, 12, 43, 8, 51]
+heap_sort(random_list_of_nums)
+print(random_list_of_nums)