it.unimi.dsi.fastutil.objects
Class ObjectHeapPriorityQueue<K>

java.lang.Object
  it.unimi.dsi.fastutil.AbstractPriorityQueue<K>
      it.unimi.dsi.fastutil.objects.ObjectHeapPriorityQueue<K>

All Implemented Interfaces:

PriorityQueue<K>

public class ObjectHeapPriorityQueue<K>
extends AbstractPriorityQueue<K>

A type-specific heap-based priority queue.

Instances of this class represent a priority queue using a heap. The heap is enlarged as needed, but it is never shrunk. Use the trim() method to reduce its size, if necessary.

Constructor Summary

ObjectHeapPriorityQueue()
Creates a new empty queue using the natural order.

ObjectHeapPriorityQueue(Comparator<? super K> c)
Creates a new empty queue with a given comparator.

ObjectHeapPriorityQueue(int capacity)
Creates a new empty queue with a given capacity and using the natural order.

ObjectHeapPriorityQueue(int capacity, Comparator<? super K> c)
Creates a new empty queue with a given capacity and comparator.

ObjectHeapPriorityQueue(K[] a)
Wraps a given array in a queue using the natural order.

ObjectHeapPriorityQueue(K[] a, Comparator<? super K> c)
Wraps a given array in a queue using a given comparator.

ObjectHeapPriorityQueue(K[] a, int size)
Wraps a given array in a queue using the natural order.

ObjectHeapPriorityQueue(K[] a, int size, Comparator<? super K> c)
Wraps a given array in a queue using a given comparator.

Method Summary

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 PriorityQueue.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 heap 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

ObjectHeapPriorityQueue

public ObjectHeapPriorityQueue(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.

ObjectHeapPriorityQueue

public ObjectHeapPriorityQueue(int capacity)

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

Parameters:

capacity - the initial capacity of this queue.

ObjectHeapPriorityQueue

public ObjectHeapPriorityQueue(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.

ObjectHeapPriorityQueue

public ObjectHeapPriorityQueue()

Creates a new empty queue using the natural order.

ObjectHeapPriorityQueue

public ObjectHeapPriorityQueue(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. 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:

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.

ObjectHeapPriorityQueue

public ObjectHeapPriorityQueue(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. 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:

a - an array.

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

ObjectHeapPriorityQueue

public ObjectHeapPriorityQueue(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. 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:

a - an array.

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

ObjectHeapPriorityQueue

public ObjectHeapPriorityQueue(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. 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:

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 PriorityQueue.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 heap 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.