# Left & Right Values of minHeapify()

I am trying to understanding the logic behind the left & right values for the minHeapify function.

Why is the index multiplied by 2?

Cheers

Hi Robert ,

This is Maida from Educative.

Initially, elements are placed in nodes in the same order as they appear in the array. Then we call _minHeapify function on all the elements to restore the heap property (starting from the bottom of the heap). The _minHeapify function swaps the values of the parent nodes with the values of their smallest child nodes until the heap property is restored.

In the given code, `left` and `right` are the indexes of the left and right child of the heap, respectively, and `index` is the index of the current parent node. We need to multiply the `left` and `right` with 2 because elements of the heap are arranged in this manner:

4, 9, 3, 2, 1, 8, 0

and It would look like this:

From the figure, it is clear that to find the left child, we need to multiply the parent index by 2 and add 1 to it. Since the right child exists right next to it we need to add 2 after multiplying the parent index by 2.

For example, if the parent is at index 3 then the left child will be at 3*2+1=7th index, and the right child will be at 3*2+2=8th index.

We hope Educative has inspired to further your learning.

Best Regards,

Maida | Developer Advocate

educative.io