CSC220 Lab 7
Due: 10:59AM, Tuesday, November 16

Your task is to write a code for an enhanced priority queue, based on the partial code provded.

Download KWOPriorityQueue.java.

This is a priority queue implmented using a binary heap. Some methods are missing in the code:

• public void swap(int a, int b)
  This is a method for swapping the data at position a and the data at position b.
• public int size()
  This is a method for obtaining the total number of elements stored in the queue.
• public Iterator iterator()
  This is a method for obtaining an iterator of the data in the increasing order with respect to the comparator. This can be implmented by a mehtod that
  1. creates a copy of the queue,
  2. executes repeated removal on the copy to build an ordered list of the data objects as a LinkedList, and then
  3. returns an iterator of the LinkedList thus created.
• public E peek()
  As required by the Queue interface, this is a method for obtaining the top element without having to remove it from the queue.
• public KWOPriorityQueue copy()
  This is a method for obtaining a copy of queue, without copying each data object E.
• public boolean modify(int a, E o)
  This is a method for substituting the element at location a with object o and then re-heap. Depending on the relationship between the data currently stored at location a and the new data o, which of the two possible conflict resolutions should be determined.

We want to test the correctness of the above queue class using a class for storing a word and a number. WordCountInt.java is an interface written for storing such pair of data. Implement this interface to write a class WordCount.java. Write a program that tests the queue using WordCount as the class to be stored. You don't have to develop a Comparator of WordCount, KWOPriorityQueue will default to the compareTo method as required in WordCountInt.java.