it.unimi.dsi.fastutil.doubles

Class DoubleArrayIndirectPriorityQueue

java.lang.Object

it.unimi.dsi.fastutil.doubles.DoubleArrayIndirectPriorityQueue

All Implemented Interfaces:

DoubleIndirectPriorityQueue, it.unimi.dsi.fastutil.IndirectPriorityQueue<java.lang.Double>

public class DoubleArrayIndirectPriorityQueue
extends java.lang.Object
implements DoubleIndirectPriorityQueue

A type-specific array-based semi-indirect priority queue.

Instances of this class use as reference list a reference array, which must be provided to each constructor, and represent a priority queue using a backing array of integer indices—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.

Field Summary

Fields

Modifier and Type	Field and Description
protected int[]	array The backing array.
protected it.unimi.dsi.fastutil.doubles.DoubleComparator	c The type-specific comparator used in this queue.
protected int	firstIndex The first index, cached, if firstIndexValid is true.
protected boolean	firstIndexValid Whether firstIndex contains a valid value.
protected double[]	refArray The reference array.
protected int	size The number of elements in this queue.

Constructor Summary

Constructors

Constructor and Description
DoubleArrayIndirectPriorityQueue(double[] refArray) Creates a new empty queue with capacity equal to the length of the reference array and using the natural order.
DoubleArrayIndirectPriorityQueue(double[] refArray, it.unimi.dsi.fastutil.doubles.DoubleComparator c) Creates a new empty queue with capacity equal to the length of the reference array and a given comparator.
DoubleArrayIndirectPriorityQueue(double[] refArray, int capacity) Creates a new empty queue with given capacity and using the natural order.
DoubleArrayIndirectPriorityQueue(double[] refArray, int[] a) Wraps a given array in a queue using the natural order.
DoubleArrayIndirectPriorityQueue(double[] refArray, int[] a, it.unimi.dsi.fastutil.doubles.DoubleComparator c) Wraps a given array in a queue using a given comparator.
DoubleArrayIndirectPriorityQueue(double[] refArray, int[] a, int size) Wraps a given array in a queue using the natural order.
DoubleArrayIndirectPriorityQueue(double[] refArray, int[] a, int size, it.unimi.dsi.fastutil.doubles.DoubleComparator c) Wraps a given array in a queue using a given comparator.
DoubleArrayIndirectPriorityQueue(double[] refArray, int capacity, it.unimi.dsi.fastutil.doubles.DoubleComparator c) Creates a new empty queue without elements with a given capacity and comparator.

Method Summary

Modifier and Type	Method and Description
void	allChanged() Signals the queue that all elements have changed.
void	changed()
void	changed(int index)
void	clear()
it.unimi.dsi.fastutil.doubles.DoubleComparator	comparator() Returns the type-specific comparator associated with this queue.
int	dequeue()
void	enqueue(int x)
protected void	ensureElement(int index) Ensures that the given index is a firstIndexValid reference.
protected void	ensureNonEmpty()
int	first()
int	front(int[] a) Writes in the provided array the front of the queue, that is, the set of indices whose elements have the same priority as the top.
int	last()
boolean	remove(int index)
int	size()
java.lang.String	toString()
void	trim() Trims the backing array so that it has exactly size() elements.

Methods inherited from class java.lang.Object

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

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

contains, isEmpty

Field Detail

refArray

protected double[] refArray

The reference array.

array

protected int[] array

The backing array.

size

protected int size

The number of elements in this queue.

c

protected it.unimi.dsi.fastutil.doubles.DoubleComparator c

The type-specific comparator used in this queue.

firstIndex

protected int firstIndex

The first index, cached, if firstIndexValid is true.

firstIndexValid

protected boolean firstIndexValid

Whether firstIndex contains a valid value.

Constructor Detail

DoubleArrayIndirectPriorityQueue

public DoubleArrayIndirectPriorityQueue(double[] refArray,
                                        int capacity,
                                        it.unimi.dsi.fastutil.doubles.DoubleComparator c)

Creates a new empty queue without elements with a given capacity and comparator.

Parameters:

refArray - the reference array.

capacity - the initial capacity of this queue.

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

DoubleArrayIndirectPriorityQueue

public DoubleArrayIndirectPriorityQueue(double[] refArray,
                                        int capacity)

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

Parameters:

refArray - the reference array.

capacity - the initial capacity of this queue.

DoubleArrayIndirectPriorityQueue

public DoubleArrayIndirectPriorityQueue(double[] refArray,
                                        it.unimi.dsi.fastutil.doubles.DoubleComparator c)

Creates a new empty queue with capacity equal to the length of the reference array and a given comparator.

Parameters:

refArray - the reference array.

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

DoubleArrayIndirectPriorityQueue

public DoubleArrayIndirectPriorityQueue(double[] refArray)

Creates a new empty queue with capacity equal to the length of the reference array and using the natural order.

Parameters:

refArray - the reference array.

DoubleArrayIndirectPriorityQueue

public DoubleArrayIndirectPriorityQueue(double[] refArray,
                                        int[] a,
                                        int size,
                                        it.unimi.dsi.fastutil.doubles.DoubleComparator 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:

refArray - the reference array.

a - an array of indices into refArray.

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

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

DoubleArrayIndirectPriorityQueue

public DoubleArrayIndirectPriorityQueue(double[] refArray,
                                        int[] a,
                                        it.unimi.dsi.fastutil.doubles.DoubleComparator 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:

refArray - the reference array.

a - an array of indices into refArray.

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

DoubleArrayIndirectPriorityQueue

public DoubleArrayIndirectPriorityQueue(double[] refArray,
                                        int[] 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:

refArray - the reference array.

a - an array of indices into refArray.

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

DoubleArrayIndirectPriorityQueue

public DoubleArrayIndirectPriorityQueue(double[] refArray,
                                        int[] 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:

refArray - the reference array.

a - an array of indices into refArray.

Method Detail

ensureNonEmpty

protected final void ensureNonEmpty()

ensureElement

protected void ensureElement(int index)

Ensures that the given index is a firstIndexValid reference.

Parameters:

index - an index in the reference array.

Throws:

java.lang.IndexOutOfBoundsException - if the given index is negative or larger than the reference array length.

enqueue

public void enqueue(int x)

Note that for efficiency reasons this method will not throw an exception when x is already in the queue. However, the queue state will become inconsistent and the following behaviour will not be predictable.

Specified by:

enqueue in interface it.unimi.dsi.fastutil.IndirectPriorityQueue<java.lang.Double>

dequeue

public int dequeue()

Specified by:

dequeue in interface it.unimi.dsi.fastutil.IndirectPriorityQueue<java.lang.Double>

first

public int first()

Specified by:

first in interface it.unimi.dsi.fastutil.IndirectPriorityQueue<java.lang.Double>

last

public int last()

Specified by:

last in interface it.unimi.dsi.fastutil.IndirectPriorityQueue<java.lang.Double>

changed

public void changed()

Specified by:

changed in interface it.unimi.dsi.fastutil.IndirectPriorityQueue<java.lang.Double>

changed

public void changed(int index)

Note that for efficiency reasons this method will not throw an exception when index is not in the queue.

Specified by:

changed in interface it.unimi.dsi.fastutil.IndirectPriorityQueue<java.lang.Double>

allChanged

public void allChanged()

Signals the queue that all elements have changed.

Specified by:

allChanged in interface it.unimi.dsi.fastutil.IndirectPriorityQueue<java.lang.Double>

remove

public boolean remove(int index)

Specified by:

remove in interface it.unimi.dsi.fastutil.IndirectPriorityQueue<java.lang.Double>

front

public int front(int[] a)

Writes in the provided array the front of the queue, that is, the set of indices whose elements have the same priority as the top.

Specified by:

front in interface it.unimi.dsi.fastutil.IndirectPriorityQueue<java.lang.Double>

Parameters:

a - an array whose initial part will be filled with the frnot (must be sized as least as the heap size).

Returns:

the number of elements of the front.

size

public int size()

Specified by:

size in interface it.unimi.dsi.fastutil.IndirectPriorityQueue<java.lang.Double>

clear

public void clear()

Specified by:

clear in interface it.unimi.dsi.fastutil.IndirectPriorityQueue<java.lang.Double>

trim

public void trim()

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

comparator

public it.unimi.dsi.fastutil.doubles.DoubleComparator comparator()

Description copied from interface: DoubleIndirectPriorityQueue

Returns the type-specific comparator associated with this queue.

Specified by:

comparator in interface DoubleIndirectPriorityQueue

Specified by:

comparator in interface it.unimi.dsi.fastutil.IndirectPriorityQueue<java.lang.Double>

Returns:

the comparator associated with this queue.

See Also:

IndirectPriorityQueue.comparator()

toString

public java.lang.String toString()

Overrides:

toString in class java.lang.Object