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

Class ComparableMinHeap<K extends Comparable<? super K>>

java.lang.Object

de.lmu.ifi.dbs.elki.utilities.datastructures.heap.ComparableMinHeap<K>

Type Parameters:

K - Key type

All Implemented Interfaces:

ObjectHeap<K>

public class ComparableMinHeap<K extends Comparable<? super K>>
extends Object
implements ObjectHeap<K>

Binary heap for primitive types.

Author:

Erich Schubert

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
private class	ComparableMinHeap.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 Comparable<Object>[]	twoheap Base heap.

Constructor Summary

Constructors

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

Method Summary

Methods

Modifier and Type	Method and Description
void	add(K o) Add a key-value pair to the heap
void	add(K 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(Comparable<Object> cur) Invoke heapify-down for the root object.
private void	heapifyUp(int twopos, Comparable<Object> cur) Heapify-Up method for 2-ary heap.
boolean	isEmpty() Is the heap empty?
K	peek() Get the current top key
K	poll() Remove the first element
K	replaceTopElement(K reinsert) Combined operation that removes the top element, and inserts a new element instead.
int	size() Query the size
String	toString()
ComparableMinHeap.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 Comparable<Object>[] 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

ComparableMinHeap

public ComparableMinHeap()

Constructor, with default size.

ComparableMinHeap

public ComparableMinHeap(int minsize)

Constructor, with given minimum size.

Parameters:

minsize - Minimum size

Method Detail

clear

public void clear()

Description copied from interface: ObjectHeap

Delete all elements from the heap.

Specified by:

clear in interface ObjectHeap<K extends Comparable<? super K>>

size

public int size()

Description copied from interface: ObjectHeap

Query the size

Specified by:

size in interface ObjectHeap<K extends Comparable<? super K>>

Returns:

Size

isEmpty

public boolean isEmpty()

Description copied from interface: ObjectHeap

Is the heap empty?

Specified by:

isEmpty in interface ObjectHeap<K extends Comparable<? super K>>

Returns:

true when the size is 0.

add

public void add(K o)

Description copied from interface: ObjectHeap

Add a key-value pair to the heap

Specified by:

add in interface ObjectHeap<K extends Comparable<? super K>>

Parameters:

o - Key

add

public void add(K key,
       int max)

Description copied from interface: ObjectHeap

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 ObjectHeap<K extends Comparable<? super K>>

Parameters:

key - Key

max - Maximum size of heap

replaceTopElement

public K replaceTopElement(K reinsert)

Description copied from interface: ObjectHeap

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

Specified by:

replaceTopElement in interface ObjectHeap<K extends Comparable<? super K>>

Parameters:

reinsert - New element to insert

Returns:

Previous top element of the heap

heapifyUp

private void heapifyUp(int twopos,
             Comparable<Object> cur)

Heapify-Up method for 2-ary heap.

Parameters:

twopos - Position in 2-ary heap.

cur - Current object

poll

public K poll()

Description copied from interface: ObjectHeap

Remove the first element

Specified by:

poll in interface ObjectHeap<K extends Comparable<? super K>>

Returns:

Top element

heapifyDown

private void heapifyDown(Comparable<Object> cur)

Invoke heapify-down for the root object.

Parameters:

cur - Object to insert.

peek

public K peek()

Description copied from interface: ObjectHeap

Get the current top key

Specified by:

peek in interface ObjectHeap<K extends Comparable<? super K>>

Returns:

Top key

toString

public String toString()

Overrides:

toString in class Object

unsortedIter

public ComparableMinHeap.UnsortedIter unsortedIter()

Description copied from interface: ObjectHeap

Get an unsorted iterator to inspect the heap.

Specified by:

unsortedIter in interface ObjectHeap<K extends Comparable<? super K>>

Returns:

Iterator