de.lmu.ifi.dbs.elki.utilities.datastructures.heap

Class IntegerMinHeap

java.lang.Object

de.lmu.ifi.dbs.elki.utilities.datastructures.heap.IntegerMinHeap

All Implemented Interfaces:

IntegerHeap

public class IntegerMinHeap
extends Object
implements IntegerHeap

Binary heap for primitive types.

Author:

Erich Schubert

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
private class	IntegerMinHeap.UnsortedIter Unsorted iterator - in heap order.

Field Summary

Fields

Modifier and Type	Field and Description
protected int	size Current size of heap.
private static int	TWO_HEAP_INITIAL_SIZE Initial size of the 2-ary heap.
protected int[]	twoheap Base heap.

Constructor Summary

Constructors

Constructor and Description
IntegerMinHeap() Constructor, with default size.
IntegerMinHeap(int minsize) Constructor, with given minimum size.

Method Summary

Methods

Modifier and Type	Method and Description
void	add(int o) Add a key-value pair to the heap
void	add(int key, int max) Add a key-value pair to the heap, except if the new element is larger than the top, and we are at design size (overflow)
void	clear() Delete all elements from the heap.
private void	heapifyDown(int cur) Invoke heapify-down for the root object.
private void	heapifyUp(int twopos, int cur) Heapify-Up method for 2-ary heap.
boolean	isEmpty() Is the heap empty?
int	peek() Get the current top key
int	poll() Remove the first element
int	replaceTopElement(int reinsert) Combined operation that removes the top element, and inserts a new element instead.
int	size() Query the size
String	toString()
IntegerMinHeap.UnsortedIter	unsortedIter() Get an unsorted iterator to inspect the heap.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Field Detail

twoheap

protected int[] twoheap

Base heap.

size

protected int size

Current size of heap.

TWO_HEAP_INITIAL_SIZE

private static final int TWO_HEAP_INITIAL_SIZE

Initial size of the 2-ary heap.

See Also:

Constant Field Values

Constructor Detail

IntegerMinHeap

public IntegerMinHeap()

Constructor, with default size.

IntegerMinHeap

public IntegerMinHeap(int minsize)

Constructor, with given minimum size.

Parameters:

minsize - Minimum size

Method Detail

clear

public void clear()

Description copied from interface: IntegerHeap

Delete all elements from the heap.

Specified by:

clear in interface IntegerHeap

size

public int size()

Description copied from interface: IntegerHeap

Query the size

Specified by:

size in interface IntegerHeap

Returns:

Size

isEmpty

public boolean isEmpty()

Description copied from interface: IntegerHeap

Is the heap empty?

Specified by:

isEmpty in interface IntegerHeap

Returns:

true when the size is 0.

add

public void add(int o)

Description copied from interface: IntegerHeap

Add a key-value pair to the heap

Specified by:

add in interface IntegerHeap

Parameters:

o - Key

add

public void add(int key,
       int max)

Description copied from interface: IntegerHeap

Add a key-value pair to the heap, except if the new element is larger than the top, and we are at design size (overflow)

Specified by:

add in interface IntegerHeap

Parameters:

key - Key

max - Maximum size of heap

replaceTopElement

public int replaceTopElement(int reinsert)

Description copied from interface: IntegerHeap

Combined operation that removes the top element, and inserts a new element instead.

Specified by:

replaceTopElement in interface IntegerHeap

Parameters:

reinsert - New element to insert

Returns:

Previous top element of the heap

heapifyUp

private void heapifyUp(int twopos,
             int cur)

Heapify-Up method for 2-ary heap.

Parameters:

twopos - Position in 2-ary heap.

cur - Current object

poll

public int poll()

Description copied from interface: IntegerHeap

Remove the first element

Specified by:

poll in interface IntegerHeap

Returns:

Top element

heapifyDown

private void heapifyDown(int cur)

Invoke heapify-down for the root object.

Parameters:

cur - Object to insert.

peek

public int peek()

Description copied from interface: IntegerHeap

Get the current top key

Specified by:

peek in interface IntegerHeap

Returns:

Top key

toString

public String toString()

Overrides:

toString in class Object

unsortedIter

public IntegerMinHeap.UnsortedIter unsortedIter()

Description copied from interface: IntegerHeap

Get an unsorted iterator to inspect the heap.

Specified by:

unsortedIter in interface IntegerHeap

Returns:

Iterator