Class DoubleHeapPriorityQueue
- java.lang.Object
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- it.unimi.dsi.fastutil.doubles.DoubleHeapPriorityQueue
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- All Implemented Interfaces:
DoublePriorityQueue
,PriorityQueue<Double>
,Serializable
public class DoubleHeapPriorityQueue extends Object implements DoublePriorityQueue, Serializable
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.- See Also:
- Serialized Form
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Constructor Summary
Constructors Constructor Description DoubleHeapPriorityQueue()
Creates a new empty queue using the natural order.DoubleHeapPriorityQueue(double[] a)
Wraps a given array in a queue using the natural order.DoubleHeapPriorityQueue(double[] a, int size)
Wraps a given array in a queue using the natural order.DoubleHeapPriorityQueue(double[] a, int size, DoubleComparator c)
Wraps a given array in a queue using a given comparator.DoubleHeapPriorityQueue(double[] a, DoubleComparator c)
Wraps a given array in a queue using a given comparator.DoubleHeapPriorityQueue(int capacity)
Creates a new empty queue with a given capacity and using the natural order.DoubleHeapPriorityQueue(int capacity, DoubleComparator c)
Creates a new empty queue with a given capacity and comparator.DoubleHeapPriorityQueue(DoubleCollection collection)
Creates a queue using the elements in a type-specific collection using the natural order.DoubleHeapPriorityQueue(DoubleCollection collection, DoubleComparator c)
Creates a queue using the elements in a type-specific collection using a given comparator.DoubleHeapPriorityQueue(DoubleComparator c)
Creates a new empty queue with a given comparator.DoubleHeapPriorityQueue(Collection<? extends Double> collection)
Creates a queue using the elements in a collection using the natural order.DoubleHeapPriorityQueue(Collection<? extends Double> collection, DoubleComparator c)
Creates a queue using the elements in a collection using 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 heap array so that it has exactlysize()
elements.-
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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DoubleHeapPriorityQueue
public DoubleHeapPriorityQueue(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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DoubleHeapPriorityQueue
public DoubleHeapPriorityQueue(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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DoubleHeapPriorityQueue
public DoubleHeapPriorityQueue(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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DoubleHeapPriorityQueue
public DoubleHeapPriorityQueue()
Creates a new empty queue using the natural order.
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DoubleHeapPriorityQueue
public DoubleHeapPriorityQueue(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. The first
size
element of the array will be rearranged so to form a heap (this is more efficient than enqueing the elements ofa
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, ornull
for the natural order.
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DoubleHeapPriorityQueue
public DoubleHeapPriorityQueue(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. 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, ornull
for the natural order.
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DoubleHeapPriorityQueue
public DoubleHeapPriorityQueue(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. The first
size
element of the array will be rearranged so to form a heap (this is more efficient than enqueing the elements ofa
one by one).- Parameters:
a
- an array.size
- the number of elements to be included in the queue.
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DoubleHeapPriorityQueue
public DoubleHeapPriorityQueue(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. 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.
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DoubleHeapPriorityQueue
public DoubleHeapPriorityQueue(DoubleCollection collection, DoubleComparator c)
Creates a queue using the elements in a type-specific collection using a given comparator.This constructor is more efficient than enqueing the elements of
collection
one by one.- Parameters:
collection
- a collection; its elements will be used to initialize the queue.c
- the comparator used in this queue, ornull
for the natural order.
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DoubleHeapPriorityQueue
public DoubleHeapPriorityQueue(DoubleCollection collection)
Creates a queue using the elements in a type-specific collection using the natural order.This constructor is more efficient than enqueing the elements of
collection
one by one.- Parameters:
collection
- a collection; its elements will be used to initialize the queue.
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DoubleHeapPriorityQueue
public DoubleHeapPriorityQueue(Collection<? extends Double> collection, DoubleComparator c)
Creates a queue using the elements in a collection using a given comparator.This constructor is more efficient than enqueing the elements of
collection
one by one.- Parameters:
collection
- a collection; its elements will be used to initialize the queue.c
- the comparator used in this queue, ornull
for the natural order.
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DoubleHeapPriorityQueue
public DoubleHeapPriorityQueue(Collection<? extends Double> collection)
Creates a queue using the elements in a collection using the natural order.This constructor is more efficient than enqueing the elements of
collection
one by one.- Parameters:
collection
- a collection; its elements will be used to initialize the queue.
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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 heap 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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