Write methods called min and max that could be added to the IntTree class and that return the smallest and largest values in the tree, respectively. For example, if a variable called tree stores the values shown in Self-Check Problem 5, the call of tree.min() should return –2 and the call of tree.max() should return 94. If the tree is empty, the methods should throw an IllegalStateException.

Data from Self Problem 5

Write the elements of the given tree in the order in which they would be seen by a preorder, inorder, and postorder traversal.

19 47 63 23 -2 94 55 28