it.unimi.dsi.fastutil.shorts

Class ShortArrayPriorityQueue

java.lang.Object

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

it.unimi.dsi.fastutil.shorts.AbstractShortPriorityQueue

it.unimi.dsi.fastutil.shorts.ShortArrayPriorityQueue

All Implemented Interfaces:

PriorityQueue<Short>, ShortPriorityQueue

public class ShortArrayPriorityQueue
extends AbstractShortPriorityQueue

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.

Field Summary

Fields

Modifier and Type	Field and Description
protected short[]	array The backing array.
protected ShortComparator	c The type-specific comparator used in this queue.
protected int	size The number of elements in this queue.

Constructor Summary

Constructors

Constructor and Description
ShortArrayPriorityQueue() Creates a new empty queue using the natural order.
ShortArrayPriorityQueue(int capacity) Creates a new empty queue with a given capacity and using the natural order.
ShortArrayPriorityQueue(int capacity, ShortComparator c) Creates a new empty queue with a given capacity and comparator.
ShortArrayPriorityQueue(short[] a) Wraps a given array in a queue using the natural order.
ShortArrayPriorityQueue(short[] a, int size) Wraps a given array in a queue using the natural order.
ShortArrayPriorityQueue(short[] a, int size, ShortComparator c) Wraps a given array in a queue using a given comparator.
ShortArrayPriorityQueue(short[] a, ShortComparator c) Wraps a given array in a queue using a given comparator.
ShortArrayPriorityQueue(ShortComparator c) Creates a new empty queue with 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.
ShortComparator	comparator() Returns the comparator associated with this sorted set, or null if it uses its elements' natural ordering.
short	dequeueShort() Dequeues an element.
void	enqueue(short x) Enqueues a new element.
short	firstShort() 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.shorts.AbstractShortPriorityQueue

dequeue, enqueue, first, last, lastShort

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

isEmpty

Methods inherited from class java.lang.Object

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

Methods inherited from interface it.unimi.dsi.fastutil.PriorityQueue

isEmpty

Field Detail

array

protected short[] array

The backing array.

size

protected int size

The number of elements in this queue.

c

protected ShortComparator c

The type-specific comparator used in this queue.

Constructor Detail

ShortArrayPriorityQueue

public ShortArrayPriorityQueue(int capacity,
                       ShortComparator 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.

ShortArrayPriorityQueue

public ShortArrayPriorityQueue(int capacity)

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

Parameters:

capacity - the initial capacity of this queue.

ShortArrayPriorityQueue

public ShortArrayPriorityQueue(ShortComparator c)

Creates a new empty queue with a given comparator.

Parameters:

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

ShortArrayPriorityQueue

public ShortArrayPriorityQueue()

Creates a new empty queue using the natural order.

ShortArrayPriorityQueue

public ShortArrayPriorityQueue(short[] a,
                       int size,
                       ShortComparator 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.

ShortArrayPriorityQueue

public ShortArrayPriorityQueue(short[] a,
                       ShortComparator 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.

ShortArrayPriorityQueue

public ShortArrayPriorityQueue(short[] 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.

ShortArrayPriorityQueue

public ShortArrayPriorityQueue(short[] 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(short x)

Description copied from interface: ShortPriorityQueue

Enqueues a new element.

Parameters:

x - the element to enqueue.

dequeueShort

public short dequeueShort()

Dequeues an element.

Note that each call to this method requires a complete scan of the backing array. Please consider caching its result.

Returns:

the dequeued element.

firstShort

public short firstShort()

Description copied from interface: ShortPriorityQueue

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<Short>

Overrides:

changed in class AbstractPriorityQueue<Short>

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 ShortComparator comparator()

Description copied from interface: ShortPriorityQueue

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

Note that this specification strengthens the one given in PriorityQueue.comparator().

Returns:

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

See Also:

PriorityQueue.comparator()