it.unimi.dsi.fastutil.doubles.DoubleArrayPriorityQueue

All Implemented Interfaces:: DoublePriorityQueue, PriorityQueue<Double>, Serializable

public class DoubleArrayPriorityQueue
extends Object
implements DoublePriorityQueue, 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.

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

See Also:: Serialized Form

Constructor Summary

Constructors
Constructor	Description
`DoubleArrayPriorityQueue()`	Creates a new empty queue using the natural order.
`DoubleArrayPriorityQueue(double[] a)`	Wraps a given array in a queue using the natural order.
`DoubleArrayPriorityQueue(double[] a, int size)`	Wraps a given array in a queue using the natural order.
`DoubleArrayPriorityQueue(double[] a, int size, DoubleComparator c)`	Wraps a given array in a queue using a given comparator.
`DoubleArrayPriorityQueue(double[] a, DoubleComparator c)`	Wraps a given array in a queue using a given comparator.
`DoubleArrayPriorityQueue(int capacity)`	Creates a new empty queue with a given capacity and using the natural order.
`DoubleArrayPriorityQueue(int capacity, DoubleComparator c)`	Creates a new empty queue with a given capacity and comparator.
`DoubleArrayPriorityQueue(DoubleComparator 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.
`DoubleComparator`	`comparator()`	Returns the comparator associated with this priority queue, or null if it uses its elements' natural ordering.
`double`	`dequeueDouble()`	Dequeues the first element from the queue.
`void`	`enqueue(double x)`	Enqueues a new element.
`double`	`firstDouble()`	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.doubles.DoublePriorityQueue

dequeue, enqueue, first, last, lastDouble

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

isEmpty

Constructor Details
- DoubleArrayPriorityQueue
  
  public DoubleArrayPriorityQueue(int capacity, DoubleComparator 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.
- DoubleArrayPriorityQueue
  
  public DoubleArrayPriorityQueue(int capacity)
  
  Creates a new empty queue with a given capacity and using the natural order.
  
  Parameters:
  
  capacity - the initial capacity of this queue.
- DoubleArrayPriorityQueue
  
  public DoubleArrayPriorityQueue(DoubleComparator c)
  
  Creates a new empty queue with a given comparator.
  
  Parameters:
  
  c - the comparator used in this queue, or null for the natural order.
- DoubleArrayPriorityQueue
  
  public DoubleArrayPriorityQueue()
  
  Creates a new empty queue using the natural order.
- DoubleArrayPriorityQueue
  
  public DoubleArrayPriorityQueue(double[] a, int size, 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:
  
  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.
- DoubleArrayPriorityQueue
  
  public DoubleArrayPriorityQueue(double[] a, 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:
  
  a - an array.
  
  c - the comparator used in this queue, or null for the natural order.
- DoubleArrayPriorityQueue
  
  public DoubleArrayPriorityQueue(double[] 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.
- DoubleArrayPriorityQueue
  
  public DoubleArrayPriorityQueue(double[] 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(double x)
  
  Description copied from interface: DoublePriorityQueue
  
  Enqueues a new element.
  
  Specified by:
  
  enqueue in interface DoublePriorityQueue
  
  Parameters:
  
  x - the element to enqueue.
  
  See Also:
  
  PriorityQueue.enqueue(Object)
- dequeueDouble
  
  public double dequeueDouble()
  
  Description copied from interface: DoublePriorityQueue
  
  Dequeues the first element from the queue.
  
  Specified by:
  
  dequeueDouble in interface DoublePriorityQueue
  
  Returns:
  
  the dequeued element.
  
  See Also:
  
  DoublePriorityQueue.dequeue()
- firstDouble
  
  public double firstDouble()
  
  Description copied from interface: DoublePriorityQueue
  
  Returns the first element of the queue.
  
  Specified by:
  
  firstDouble in interface DoublePriorityQueue
  
  Returns:
  
  the first element.
  
  See Also:
  
  DoublePriorityQueue.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<Double>
- size
  
  public int size()
  
  Description copied from interface: PriorityQueue
  
  Returns the number of elements in this queue.
  
  Specified by:
  
  size in interface PriorityQueue<Double>
  
  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<Double>
- trim
  
  public void trim()
  
  Trims the underlying array so that it has exactly size() elements.
- comparator
  
  public DoubleComparator comparator()
  
  Description copied from interface: DoublePriorityQueue
  
  Returns the comparator associated with this priority queue, or null if it uses its elements' natural ordering.
  Note that this specification strengthens the one given in PriorityQueue.comparator().
  
  Specified by:
  
  comparator in interface DoublePriorityQueue
  
  Specified by:
  
  comparator in interface PriorityQueue<Double>
  
  Returns:
  
  the comparator associated with this priority queue.
  
  See Also:
  
  PriorityQueue.comparator()

Class DoubleArrayPriorityQueue

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Methods inherited from interface it.unimi.dsi.fastutil.doubles.DoublePriorityQueue

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

Constructor Details

Method Details