structure5
Class VectorHeap<E extends Comparable<E>>

java.lang.Object
  structure5.VectorHeap<E>

All Implemented Interfaces:

PriorityQueue<E>

public class VectorHeap<E extends Comparable<E>>
extends Object
implements PriorityQueue<E>

This class implements a priority queue based on a traditional array-based heap. Most heap operations, including insert and remove, execute in logarithmic time, but the minimum element can be returned in constant time.

Example usage:

To print out a list of programmers sorted by age we could use the following:

 public static void main(String[] argv){
        //initialize a new fib heap
        VectorHeap programmers = new VectorHeap();

        //add programmers and their ages to heap
        //ages current of 7/22/2002
        //add programmers and their ages to heap
        //ages current of 7/22/2002
        programmers.add(new ComparableAssociation(new Integer(22), "Evan"));
        programmers.add(new ComparableAssociation(new Integer(19), "Chris"));
        programmers.add(new ComparableAssociation(new Integer(20), "Shimon"));
        programmers.add(new ComparableAssociation(new Integer(21), "Diane"));
        programmers.add(new ComparableAssociation(new Integer(21), "Lida"));    
        programmers.add(new ComparableAssociation(new Integer(20), "Rob"));     
        programmers.add(new ComparableAssociation(new Integer(20), "Sean"));    

        //print out programmers 
        while(!programmers.isEmpty()){
            ComparableAssociation p = (ComparableAssociation)programmers.remove();
            System.out.println(p.getValue() + " is " + p.getKey() + " years old.");
        }
 }
 

Constructor Summary

VectorHeap()
Construct a new priority queue

VectorHeap(Vector<E> v)
Construct a new priority queue from an unordered vector

Method Summary

void	add(E value) Add a value to the priority queue.
void	clear() Remove all the elements from the queue.
E	getFirst() Fetch lowest valued (highest priority) item from queue.
boolean	isEmpty() Determine if the queue is empty.
E	remove() Returns the minimum value from the queue.
int	size() Determine the size of the queue.
String	toString() Construct a string representation of the heap.

Methods inherited from class java.lang.Object

equals, getClass, hashCode, notify, notifyAll, wait, wait, wait

Constructor Detail

VectorHeap

public VectorHeap()

Construct a new priority queue

VectorHeap

public VectorHeap(Vector<E> v)

Construct a new priority queue from an unordered vector

Method Detail

getFirst

public E getFirst()

Fetch lowest valued (highest priority) item from queue.

Specified by:

getFirst in interface PriorityQueue<E extends Comparable<E>>

Returns:

The smallest value from queue.

remove

public E remove()

Returns the minimum value from the queue.

Specified by:

remove in interface PriorityQueue<E extends Comparable<E>>

Returns:

The minimum value in the queue.

add

public void add(E value)

Add a value to the priority queue.

Specified by:

add in interface PriorityQueue<E extends Comparable<E>>

Parameters:

value - The value to be added.

isEmpty

public boolean isEmpty()

Determine if the queue is empty.

Specified by:

isEmpty in interface PriorityQueue<E extends Comparable<E>>

Returns:

True if the queue is empty.

size

public int size()

Determine the size of the queue.

Specified by:

size in interface PriorityQueue<E extends Comparable<E>>

Returns:

The number of elements within the queue.

clear

public void clear()

Remove all the elements from the queue.

Specified by:

clear in interface PriorityQueue<E extends Comparable<E>>

toString

public String toString()

Construct a string representation of the heap.

Overrides:

toString in class Object

Returns:

The string representing the heap.