Package it.unimi.dsi.fastutil.floats

Class FloatArrayPriorityQueue

java.lang.Object

it.unimi.dsi.fastutil.floats.FloatArrayPriorityQueue

All Implemented Interfaces:

FloatPriorityQueue, PriorityQueue<Float>, Serializable

public class FloatArrayPriorityQueue
extends Object
implements FloatPriorityQueue, Serializable

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.

See Also:

• Serialized Form

Implementation Specification:

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

Constructor Summary

Constructors

Constructor	Description
FloatArrayPriorityQueue()	Creates a new empty queue using the natural order.
FloatArrayPriorityQueue(float[] a)	Wraps a given array in a queue using the natural order.
FloatArrayPriorityQueue(float[] a, int size)	Wraps a given array in a queue using the natural order.
FloatArrayPriorityQueue(float[] a, int size, FloatComparator c)	Wraps a given array in a queue using a given comparator.
FloatArrayPriorityQueue(float[] a, FloatComparator c)	Wraps a given array in a queue using a given comparator.
FloatArrayPriorityQueue(int capacity)	Creates a new empty queue with a given capacity and using the natural order.
FloatArrayPriorityQueue(int capacity, FloatComparator c)	Creates a new empty queue with a given capacity and comparator.
FloatArrayPriorityQueue(FloatComparator c)	Creates a new empty queue with a given comparator.

Method Summary

Modifier and Type	Method	Description
void	changed()	Notifies the queue that the first element has changed (optional operation).
void	clear()	Removes all elements from this queue.
FloatComparator	comparator()	Returns the comparator associated with this priority queue, or null if it uses its elements' natural ordering.
float	dequeueFloat()	Dequeues the first element from the queue.
void	enqueue(float x)	Enqueues a new element.
float	firstFloat()	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 java.lang.Object

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

Methods inherited from interface it.unimi.dsi.fastutil.floats.FloatPriorityQueue

dequeue, enqueue, first, last, lastFloat

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

isEmpty

Constructor Details

FloatArrayPriorityQueue

public FloatArrayPriorityQueue(int capacity,
 FloatComparator 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.

FloatArrayPriorityQueue

public FloatArrayPriorityQueue(int capacity)

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

Parameters:

capacity - the initial capacity of this queue.

FloatArrayPriorityQueue

public FloatArrayPriorityQueue(FloatComparator c)

Creates a new empty queue with a given comparator.

Parameters:

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

FloatArrayPriorityQueue

public FloatArrayPriorityQueue()

Creates a new empty queue using the natural order.

FloatArrayPriorityQueue

public FloatArrayPriorityQueue(float[] a,
 int size,
 FloatComparator 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.

FloatArrayPriorityQueue

public FloatArrayPriorityQueue(float[] a,
 FloatComparator 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.

FloatArrayPriorityQueue

public FloatArrayPriorityQueue(float[] 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.

FloatArrayPriorityQueue

public FloatArrayPriorityQueue(float[] 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 Details

enqueue

public void enqueue(float x)

Description copied from interface: FloatPriorityQueue

Enqueues a new element.

Specified by:

enqueue in interface FloatPriorityQueue

Parameters:

x - the element to enqueue.

See Also:

• PriorityQueue.enqueue(Object)

dequeueFloat

public float dequeueFloat()

Description copied from interface: FloatPriorityQueue

Dequeues the first element from the queue.

Specified by:

dequeueFloat in interface FloatPriorityQueue

Returns:

the dequeued element.

See Also:

• FloatPriorityQueue.dequeue()

firstFloat

public float firstFloat()

Description copied from interface: FloatPriorityQueue

Returns the first element of the queue.

Specified by:

firstFloat in interface FloatPriorityQueue

Returns:

the first element.

See Also:

• FloatPriorityQueue.first()

changed

public void changed()

Description copied from interface: PriorityQueue

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

This default implementation just throws an UnsupportedOperationException.

Specified by:

changed in interface PriorityQueue<Float>

size

public int size()

Description copied from interface: PriorityQueue

Returns the number of elements in this queue.

Specified by:

size in interface PriorityQueue<Float>

Returns:

the number of elements in this queue.

clear

public void clear()

Description copied from interface: PriorityQueue

Removes all elements from this queue.

Specified by:

clear in interface PriorityQueue<Float>

trim

public void trim()

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

comparator

public FloatComparator comparator()

Description copied from interface: FloatPriorityQueue

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

Specified by:

comparator in interface FloatPriorityQueue

Specified by:

comparator in interface PriorityQueue<Float>

Returns:

the comparator associated with this priority queue.

See Also:

• PriorityQueue.comparator()