Class DoubleArrayPriorityQueue
- java.lang.Object
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- it.unimi.dsi.fastutil.doubles.DoubleArrayPriorityQueue
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- 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
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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.
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Method Summary
All Methods Instance Methods Concrete Methods 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 exactlysize()
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Methods inherited from class java.lang.Object
equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
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Methods inherited from interface it.unimi.dsi.fastutil.doubles.DoublePriorityQueue
dequeue, enqueue, first, last, lastDouble
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Methods inherited from interface it.unimi.dsi.fastutil.PriorityQueue
isEmpty
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Constructor Detail
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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, ornull
for the natural order.
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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.
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DoubleArrayPriorityQueue
public DoubleArrayPriorityQueue(DoubleComparator c)
Creates a new empty queue with a given comparator.- Parameters:
c
- the comparator used in this queue, ornull
for the natural order.
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DoubleArrayPriorityQueue
public DoubleArrayPriorityQueue()
Creates a new empty queue using the natural order.
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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, ornull
for the natural order.
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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, ornull
for the natural order.
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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.
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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.
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Method Detail
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enqueue
public void enqueue(double x)
Description copied from interface:DoublePriorityQueue
Enqueues a new element.- Specified by:
enqueue
in interfaceDoublePriorityQueue
- Parameters:
x
- the element to enqueue.- See Also:
PriorityQueue.enqueue(Object)
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dequeueDouble
public double dequeueDouble()
Description copied from interface:DoublePriorityQueue
Dequeues the first element from the queue.- Specified by:
dequeueDouble
in interfaceDoublePriorityQueue
- Returns:
- the dequeued element.
- See Also:
DoublePriorityQueue.dequeue()
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firstDouble
public double firstDouble()
Description copied from interface:DoublePriorityQueue
Returns the first element of the queue.- Specified by:
firstDouble
in interfaceDoublePriorityQueue
- Returns:
- the first element.
- See Also:
DoublePriorityQueue.first()
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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 interfacePriorityQueue<Double>
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size
public int size()
Description copied from interface:PriorityQueue
Returns the number of elements in this queue.- Specified by:
size
in interfacePriorityQueue<Double>
- Returns:
- the number of elements in this queue.
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clear
public void clear()
Description copied from interface:PriorityQueue
Removes all elements from this queue.- Specified by:
clear
in interfacePriorityQueue<Double>
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trim
public void trim()
Trims the underlying array so that it has exactlysize()
elements.
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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 interfaceDoublePriorityQueue
- Specified by:
comparator
in interfacePriorityQueue<Double>
- Returns:
- the comparator associated with this priority queue.
- See Also:
PriorityQueue.comparator()
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