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BJP3 Exercise 11.6: countUnique

Language/Type: Java Collections Sets
Author: Marty Stepp (on 2013/04/01)

Write a method countUnique that takes a List of integers as a parameter and returns the number of unique integer values in the list. Use a Set as auxiliary storage to help you solve this problem.

For example, if a list contains the values [3, 7, 3, -1, 2, 3, 7, 2, 15, 15], your method should return 5. The empty list contains 0 unique values.

Type your solution here:

This is a method problem. Write a Java method as described. Do not write a complete program or class; just the method(s) above.

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