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


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YOUR TASKS FOR TODAY
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1. In MergeSort.java understand well the method mergeSortIterative

2. In BinaryTree.java
a) implement the method numberOfLeaves() - the method returns the number of leaves
b) implement the method clone() - creates a copy of this
c) implement the method equals(Object obj) - that checks if obj has the same tree structure as this with the same data.
d) implement the method listOfAllItems()() - that returns the list of all items in the tree
e) implement the method heightIterative() - it computes the height of the tree without using recursion

- Write test cases to check that your methods are implemented correctly

