CIS2168
TEN MINUTE TEST # 10
November 16, 2010

(10)	1. 
	(a) What makes for a good hash function?
	(b) What is a collision?
	(c) What is collision resolution?











(15)	2. The Comparator interface defines the method 
		int compare(Pair o1, Pair o2).
	   (a) Implement that interface and methods for a class Pair that 
	   has two fields: key, a String, and value, also a String.
	   We want the compare to be based only on the key field.
	   (b) Show how we will use this comparator to sort an array of Pair.













	
(15)	3. Implement the static function 
		public static int leaves(BinaryTree<Integer> root)
	   which returns the sum of all the integers stored at leaves
	   of the tree rooted at root.