Given the following:

public void perfectify$()\{$

$//$TODO: Assignment Part $3$

$\}$

Converts the binary tree into a perfect tree by adding nodes with the value $-1.$

$*$ A perfect binary tree is one where all leaves are at the same level and every branch node has two children.

$*$ Another way of thinking of it is that you are adding dummy nodes to the tree until every path from the root to a leaf is the same length. You may need to create a perfectify helper method for this recursive method. Thanks.