it.unimi.dsi.fastutil.objects

Class ObjectArrayPriorityQueue<K>

java.lang.Object

it.unimi.dsi.fastutil.AbstractPriorityQueue<K>

it.unimi.dsi.fastutil.objects.ObjectArrayPriorityQueue<K>

All Implemented Interfaces:

PriorityQueue<K>

public class ObjectArrayPriorityQueue<K>
extends AbstractPriorityQueue<K>

A type-specific array-based priority queue.

Instances of this class represent a priority queue using a backing array—all operations are performed directly on the array. The array is enlarged as needed, but it is never shrunk. Use the trim() method to reduce its size, if necessary.

This implementation is extremely inefficient, but it is difficult to beat when the size of the queue is very small.

Constructor Summary

Constructors

Constructor and Description
ObjectArrayPriorityQueue() Creates a new empty queue using the natural order.
ObjectArrayPriorityQueue(Comparator<? super K> c) Creates a new empty queue with a given comparator.
ObjectArrayPriorityQueue(int capacity) Creates a new empty queue with a given capacity and using the natural order.
ObjectArrayPriorityQueue(int capacity, Comparator<? super K> c) Creates a new empty queue with a given capacity and comparator.
ObjectArrayPriorityQueue(K[] a) Wraps a given array in a queue using the natural order.
ObjectArrayPriorityQueue(K[] a, Comparator<? super K> c) Wraps a given array in a queue using a given comparator.
ObjectArrayPriorityQueue(K[] a, int size) Wraps a given array in a queue using the natural order.
ObjectArrayPriorityQueue(K[] a, int size, Comparator<? super K> c) Wraps a given array in a queue using a given comparator.

Method Summary

Methods

Modifier and Type	Method and Description
void	changed() Notifies the queue that the first element has changed (optional operation).
void	clear() Removes all elements from this queue.
Comparator<? super K>	comparator() Returns the comparator associated with this queue, or null if it uses its elements' natural ordering.
K	dequeue() Dequeues the first element from the queue.
void	enqueue(K x) Enqueues a new element.
K	first() Returns the first element of the queue.
int	size() Returns the number of elements in this queue.
void	trim() Trims the underlying array so that it has exactly size() elements.

Methods inherited from class it.unimi.dsi.fastutil.AbstractPriorityQueue

isEmpty, last

Methods inherited from class java.lang.Object

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

Constructor Detail

ObjectArrayPriorityQueue

public ObjectArrayPriorityQueue(int capacity,
                        Comparator<? super K> c)

Creates a new empty queue with a given capacity and comparator.

Parameters:

capacity - the initial capacity of this queue.

c - the comparator used in this queue, or null for the natural order.

ObjectArrayPriorityQueue

public ObjectArrayPriorityQueue(int capacity)

Creates a new empty queue with a given capacity and using the natural order.

Parameters:

capacity - the initial capacity of this queue.

ObjectArrayPriorityQueue

public ObjectArrayPriorityQueue(Comparator<? super K> c)

Creates a new empty queue with a given comparator.

Parameters:

c - the comparator used in this queue, or null for the natural order.

ObjectArrayPriorityQueue

public ObjectArrayPriorityQueue()

Creates a new empty queue using the natural order.

ObjectArrayPriorityQueue

public ObjectArrayPriorityQueue(K[] a,
                        int size,
                        Comparator<? super K> c)

Wraps a given array in a queue using a given comparator.

The queue returned by this method will be backed by the given array.

Parameters:

a - an array.

size - the number of elements to be included in the queue.

c - the comparator used in this queue, or null for the natural order.

ObjectArrayPriorityQueue

public ObjectArrayPriorityQueue(K[] a,
                        Comparator<? super K> c)

Wraps a given array in a queue using a given comparator.

The queue returned by this method will be backed by the given array.

Parameters:

a - an array.

c - the comparator used in this queue, or null for the natural order.

ObjectArrayPriorityQueue

public ObjectArrayPriorityQueue(K[] a,
                        int size)

Wraps a given array in a queue using the natural order.

The queue returned by this method will be backed by the given array.

Parameters:

a - an array.

size - the number of elements to be included in the queue.

ObjectArrayPriorityQueue

public ObjectArrayPriorityQueue(K[] a)

Wraps a given array in a queue using the natural order.

The queue returned by this method will be backed by the given array.

Parameters:

a - an array.

Method Detail

enqueue

public void enqueue(K x)

Description copied from interface: PriorityQueue

Enqueues a new element.

Parameters:

x - the element to enqueue..

dequeue

public K dequeue()

Description copied from interface: PriorityQueue

Dequeues the first element from the queue.

Returns:

the dequeued element.

first

public K first()

Description copied from interface: PriorityQueue

Returns the first element of the queue.

Returns:

the first element.

changed

public void changed()

Description copied from interface: PriorityQueue

Notifies the queue that the first element has changed (optional operation).

Specified by:

changed in interface PriorityQueue<K>

Overrides:

changed in class AbstractPriorityQueue<K>

size

public int size()

Description copied from interface: PriorityQueue

Returns the number of elements in this queue.

Returns:

the number of elements in this queue.

clear

public void clear()

Description copied from interface: PriorityQueue

Removes all elements from this queue.

trim

public void trim()

Trims the underlying array so that it has exactly size() elements.

comparator

public Comparator<? super K> comparator()

Description copied from interface: PriorityQueue

Returns the comparator associated with this queue, or null if it uses its elements' natural ordering.

Returns:

the comparator associated with this sorted set, or null if it uses its elements' natural ordering.