Question

Suppose we have a min heap with some elements which satisfy the heap property.
What happens if I change the algorithm from min heap to max heap without rearrange the internal array?

That is, if I keep the array unchanged, what happens when I append an element to the internal array?

Answer 1

Consider the following example from Wikipedia:

The array representation of this would look like this:

[1, 2, 3, 17, 19, 36, 7, 25, 100]

Now we “change” the heap from min to max, but without rearranging the elements and insert a new element “25”. The array position would be 9 so the parent node is “19” at position 4.

After inserting we must repeatedly compare the new item with its parent to ensure heap property (now max-heap => parent must be greater than child). Thus we must swap “25” with “19”, “2” and “1” until it is the root node.

Now the max-heap property holds for the root node (its children are indeed smaller), but not for the other nodes, e.g. “3” is still the parent of “7” and violates the max-heap condition.

To conclude this: Doing what you describe does not change the min-heap to a max-heap.