org.opencores.util
Class Heap

java.lang.Object
  |
  +--java.util.AbstractCollection
        |
        +--java.util.AbstractList
              |
              +--java.util.Vector
                    |
                    +--org.opencores.util.Heap

public class Heap

extends java.util.Vector

Priority queue using heap. add and remove require maximum O(log(N)) time.

See Also:

Serialized Form

Fields inherited from class java.util.Vector

capacityIncrement, elementCount, elementData, serialVersionUID

Fields inherited from class java.util.AbstractList

modCount

Constructor Summary

Heap()
Constructs a heap with no elements.

Heap(java.lang.Comparable[] array)
Constructs the heap in O(N) time, using a technique similar to bottom-up construction.

Method Summary

void	add(java.lang.Comparable element) Inserts key into the heap, and then upheaps that key to a position where the heap property is satisfied.
private void	exchange(int i, int j) Exchanges the elements stored at the two locations
private static int	left(int i) Returns the Vector index of the left child.
private static int	parent(int i) Returns the Vector index of the parent
java.lang.Comparable	remove() Removes the minimum (top) element from the Heap, decreases the size of the heap by one, and returns the minimum element.
boolean	remove(java.lang.Comparable element) Removes specified element from the Heap, decreases the size of the heap by one, and returns true if successful.
void	repair() Reconstruct the heap in O(N) time.
private static int	right(int i) Returns the Vector index of the right child.
private void	sift(int i) Also known as downheap, restores the heap condition starting at node i and working its way down.

Methods inherited from class java.util.Vector

add, add, addAll, addAll, addElement, capacity, clear, clone, contains, containsAll, copyInto, elementAt, elements, ensureCapacity, ensureCapacityHelper, equals, firstElement, get, hashCode, indexOf, indexOf, insertElementAt, isEmpty, lastElement, lastIndexOf, lastIndexOf, remove, remove, removeAll, removeAllElements, removeElement, removeElementAt, removeRange, retainAll, set, setElementAt, setSize, size, subList, toArray, toArray, toString, trimToSize

Methods inherited from class java.util.AbstractList

iterator, listIterator, listIterator

Methods inherited from class java.lang.Object

, finalize, getClass, notify, notifyAll, registerNatives, wait, wait, wait

Constructor Detail

Heap

public Heap(java.lang.Comparable[] array)

Constructs the heap in O(N) time, using a technique similar to bottom-up construction.

Parameters:

array - constructs heap based on this array

Heap

public Heap()

Constructs a heap with no elements.

Method Detail

repair

public void repair()

Reconstruct the heap in O(N) time.

left

private static final int left(int i)

Returns the Vector index of the left child.

Parameters:

i - index

right

private static final int right(int i)

Returns the Vector index of the right child.

Parameters:

i - index

parent

private static final int parent(int i)

Returns the Vector index of the parent

exchange

private final void exchange(int i,
                            int j)

Exchanges the elements stored at the two locations

Parameters:

i - index of first element

j - index of second element

sift

private final void sift(int i)

Also known as downheap, restores the heap condition starting at node i and working its way down.

Parameters:

i - index of node to sift

remove

public java.lang.Comparable remove()
                            throws java.util.NoSuchElementException

Removes the minimum (top) element from the Heap, decreases the size of the heap by one, and returns the minimum element.

Returns:

minimum object

add

public void add(java.lang.Comparable element)

Inserts key into the heap, and then upheaps that key to a position where the heap property is satisfied.

Parameters:

elt - object to insert

remove

public boolean remove(java.lang.Comparable element)
               throws java.util.NoSuchElementException

Removes specified element from the Heap, decreases the size of the heap by one, and returns true if successful.

Parameters:

element - element to delete

Returns:

true if object found false otherwise