it.unimi.dsi.fastutil.longs

Class LongHeapIndirectPriorityQueue

java.lang.Object

it.unimi.dsi.fastutil.AbstractIndirectPriorityQueue<Long>

it.unimi.dsi.fastutil.longs.LongHeapSemiIndirectPriorityQueue

it.unimi.dsi.fastutil.longs.LongHeapIndirectPriorityQueue

All Implemented Interfaces:

IndirectPriorityQueue<Long>

public class LongHeapIndirectPriorityQueue
extends LongHeapSemiIndirectPriorityQueue

A type-specific heap-based indirect priority queue.

Instances of this class use an additional inversion array, of the same length of the reference array, to keep track of the heap position containing a given element of the reference array. The priority queue is represented using a heap. The heap is enlarged as needed, but it is never shrunk. Use the LongHeapSemiIndirectPriorityQueue.trim() method to reduce its size, if necessary.

This implementation does not allow one to enqueue several times the same index.

Field Summary

Fields

Modifier and Type	Field and Description
protected int[]	inv The inversion array.

Fields inherited from class it.unimi.dsi.fastutil.longs.LongHeapSemiIndirectPriorityQueue

c, heap, refArray, size

Constructor Summary

Constructors

Constructor and Description
LongHeapIndirectPriorityQueue(long[] refArray) Creates a new empty queue with capacity equal to the length of the reference array and using the natural order.
LongHeapIndirectPriorityQueue(long[] refArray, int capacity) Creates a new empty queue with a given capacity and using the natural order.
LongHeapIndirectPriorityQueue(long[] refArray, int[] a) Wraps a given array in a queue using the natural order.
LongHeapIndirectPriorityQueue(long[] refArray, int[] a, int size) Wraps a given array in a queue using the natural order.
LongHeapIndirectPriorityQueue(long[] refArray, int[] a, int size, LongComparator c) Wraps a given array in a queue using a given comparator.
LongHeapIndirectPriorityQueue(long[] refArray, int[] a, LongComparator c) Wraps a given array in a queue using a given comparator.
LongHeapIndirectPriorityQueue(long[] refArray, int capacity, LongComparator c) Creates a new empty queue with a given capacity and comparator.
LongHeapIndirectPriorityQueue(long[] refArray, LongComparator c) Creates a new empty queue with capacity equal to the length of the reference array and a given comparator.

Method Summary

Methods

Modifier and Type	Method and Description
void	allChanged() Rebuilds this heap in a bottom-up fashion.
void	changed() Notifies this queue that the first element has changed (optional operation).
void	changed(int index) Notifies this queue that the specified element has changed (optional operation).
void	clear() Removes all elements from this queue.
boolean	contains(int index) Checks whether a given index belongs to this queue (optional operation).
int	dequeue() Dequeues the first element from this queue.
void	enqueue(int x) Enqueues a new element.
boolean	remove(int index) Removes the specified element from this queue (optional operation).

Methods inherited from class it.unimi.dsi.fastutil.longs.LongHeapSemiIndirectPriorityQueue

comparator, ensureElement, first, front, size, toString, trim

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

isEmpty, last

Methods inherited from class java.lang.Object

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

Field Detail

inv

protected int[] inv

The inversion array.

Constructor Detail

LongHeapIndirectPriorityQueue

public LongHeapIndirectPriorityQueue(long[] refArray,
                             int capacity,
                             LongComparator c)

Creates a new empty queue 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.

LongHeapIndirectPriorityQueue

public LongHeapIndirectPriorityQueue(long[] refArray,
                             int capacity)

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

Parameters:

refArray - the reference array.

capacity - the initial capacity of this queue.

LongHeapIndirectPriorityQueue

public LongHeapIndirectPriorityQueue(long[] refArray,
                             LongComparator 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.

LongHeapIndirectPriorityQueue

public LongHeapIndirectPriorityQueue(long[] 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.

LongHeapIndirectPriorityQueue

public LongHeapIndirectPriorityQueue(long[] refArray,
                             int[] a,
                             int size,
                             LongComparator 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. The first size element of the array will be rearranged so to form a heap (this is more efficient than enqueing the elements of a one by one).

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.

LongHeapIndirectPriorityQueue

public LongHeapIndirectPriorityQueue(long[] refArray,
                             int[] a,
                             LongComparator 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. The elements of the array will be rearranged so to form a heap (this is more efficient than enqueing the elements of a one by one).

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.

LongHeapIndirectPriorityQueue

public LongHeapIndirectPriorityQueue(long[] 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. The first size element of the array will be rearranged so to form a heap (this is more efficient than enqueing the elements of a one by one).

Parameters:

refArray - the reference array.

a - an array of indices into refArray.

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

LongHeapIndirectPriorityQueue

public LongHeapIndirectPriorityQueue(long[] 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. The elements of the array will be rearranged so to form a heap (this is more efficient than enqueing the elements of a one by one).

Parameters:

refArray - the reference array.

a - an array of indices into refArray.

Method Detail

enqueue

public void enqueue(int x)

Description copied from interface: IndirectPriorityQueue

Enqueues a new element.

Specified by:

enqueue in interface IndirectPriorityQueue<Long>

Overrides:

enqueue in class LongHeapSemiIndirectPriorityQueue

Parameters:

x - the element to enqueue..

contains

public boolean contains(int index)

Description copied from interface: IndirectPriorityQueue

Checks whether a given index belongs to this queue (optional operation).

Specified by:

contains in interface IndirectPriorityQueue<Long>

Overrides:

contains in class AbstractIndirectPriorityQueue<Long>

Returns:

true if the specified index belongs to this queue.

dequeue

public int dequeue()

Description copied from interface: IndirectPriorityQueue

Dequeues the first element from this queue.

Specified by:

dequeue in interface IndirectPriorityQueue<Long>

Overrides:

dequeue in class LongHeapSemiIndirectPriorityQueue

Returns:

the dequeued element.

changed

public void changed()

Description copied from class: LongHeapSemiIndirectPriorityQueue

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

The caller must guarantee that when this method is called the index of the first element appears just once in the queue. Failure to do so will bring the queue in an inconsistent state, and will cause unpredictable behaviour.

Specified by:

changed in interface IndirectPriorityQueue<Long>

Overrides:

changed in class LongHeapSemiIndirectPriorityQueue

changed

public void changed(int index)

Description copied from interface: IndirectPriorityQueue

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

Note that the specified element must belong to this queue.

Specified by:

changed in interface IndirectPriorityQueue<Long>

Overrides:

changed in class AbstractIndirectPriorityQueue<Long>

Parameters:

index - the element that has changed.

allChanged

public void allChanged()

Rebuilds this heap in a bottom-up fashion.

Specified by:

allChanged in interface IndirectPriorityQueue<Long>

Overrides:

allChanged in class LongHeapSemiIndirectPriorityQueue

remove

public boolean remove(int index)

Description copied from interface: IndirectPriorityQueue

Removes the specified element from this queue (optional operation).

Specified by:

remove in interface IndirectPriorityQueue<Long>

Overrides:

remove in class AbstractIndirectPriorityQueue<Long>

Parameters:

index - the element to be removed.

Returns:

true if the index was in the queue.

clear

public void clear()

Description copied from interface: IndirectPriorityQueue

Removes all elements from this queue.

Specified by:

clear in interface IndirectPriorityQueue<Long>

Overrides:

clear in class LongHeapSemiIndirectPriorityQueue