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

java.lang.Object
  extended by it.unimi.dsi.fastutil.AbstractPriorityQueue<K>
      extended by 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 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 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.