All Packages  Class Hierarchy  This Package  Previous  Next  Index

Class DataStructures.PairHeap 

java.lang.Object
    |
    +----DataStructures.PairHeap
public class PairHeap
extends Object
implements PriorityQueue
Implements a pairing heap. Supports a decreaseKey operation, but requires use of addItem instead of insert. Heap order is always maintained; no lazy operations allowed. Note that all "matching" is based on the compares method.

See Also:
PairNode

Constructor Index

o PairHeap()
Construct the pairing heap.

Method Index

o addItem(Comparable)
Insert into the priority queue, and return a PairNode that can be used by decreaseKey.
o decreaseKey(PairNode, Comparable)
Change the value of the item stored in the pairing heap.
o deleteMin()
Remove the smallest item from the priority queue.
o findMin()
Find the smallest item in the priority queue.
o insert(Comparable)
Insert into the priority queue.
o isEmpty()
Test if the priority queue is logically empty.
o main(String[])
o makeEmpty()
Make the priority queue logically empty.

Constructors

o PairHeap 
public PairHeap()
Construct the pairing heap.

Methods

o insert 
public void insert(Comparable x)
Insert into the priority queue. Duplicates are allowed.

Parameters:
x - the item to insert.
o addItem 
public PairNode addItem(Comparable x)
Insert into the priority queue, and return a PairNode that can be used by decreaseKey. Duplicates are allowed.

Parameters:
x - the item to insert.
Returns:
the node containing the newly inserted item.
o findMin 
public Comparable findMin() throws Underflow
Find the smallest item in the priority queue.

Returns:
the smallest item.
Throws: Underflow
if the priority queue is empty.
o deleteMin 
public Comparable deleteMin() throws Underflow
Remove the smallest item from the priority queue.

Throws: Underflow
if the priority queue is empty.
o decreaseKey 
public void decreaseKey(PairNode p,
                        Comparable newVal) throws IllegalValue
Change the value of the item stored in the pairing heap.

Parameters:
p - any node returned by addItem.
newVal - the new value, which must be smaller than the currently stored value.
Throws: IllegalValue
if newVal is larger than the currently stored value.
o isEmpty 
public boolean isEmpty()
Test if the priority queue is logically empty.

Returns:
true if empty, false otherwise.
o makeEmpty 
public void makeEmpty()
Make the priority queue logically empty.

o main 
public static void main(String[] args)
All Packages  Class Hierarchy  This Package  Previous  Next  Index