The topics of today's lab are:
- binary search trees


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YOUR TASKS FOR TODAY
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Extend the implementation of BSTs to support the following operations:
1) For each node store in the node the size of the subtree rooted at this node
2) For each node store in the node the height of the subtree rooted at this node
This way, your BST will support size() and height() in O(1) time

Write a method of the class BinarySearchTree that returns a sorted ArrayList with all elements of the tree.
ArrayList<T> toSortedArray()


Test all your methods
