Class ObjectHeapPriorityQueue<K>
- java.lang.Object
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- it.unimi.dsi.fastutil.objects.ObjectHeapPriorityQueue<K>
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- All Implemented Interfaces:
PriorityQueue<K>
,Serializable
public class ObjectHeapPriorityQueue<K> extends Object implements PriorityQueue<K>, 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 ObjectHeapPriorityQueue()
Creates a new empty queue using the natural order.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(Collection<? extends K> collection)
Creates a queue using the elements in a collection using the natural order.ObjectHeapPriorityQueue(Collection<? extends K> collection, Comparator<? super K> c)
Creates a queue using the elements in a collection using a given comparator.ObjectHeapPriorityQueue(Comparator<? super K> c)
Creates a new empty queue with a given comparator.ObjectHeapPriorityQueue(K[] a)
Wraps a given array in a queue using the natural order.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.ObjectHeapPriorityQueue(K[] a, Comparator<? super K> c)
Wraps a given array in a queue 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.Comparator<? super K>
comparator()
Returns the comparator associated with this queue, ornull
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 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.PriorityQueue
isEmpty, last
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Constructor Detail
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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, ornull
for the natural order.
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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.
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ObjectHeapPriorityQueue
public ObjectHeapPriorityQueue(Comparator<? super K> 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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ObjectHeapPriorityQueue
public ObjectHeapPriorityQueue()
Creates a new empty queue using the natural order.
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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 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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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, ornull
for the natural order.
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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 ofa
one by one).- Parameters:
a
- an array.size
- the number of elements to be included in the queue.
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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.
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ObjectHeapPriorityQueue
public ObjectHeapPriorityQueue(Collection<? extends K> collection, Comparator<? super K> 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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ObjectHeapPriorityQueue
public ObjectHeapPriorityQueue(Collection<? extends K> 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(K x)
Description copied from interface:PriorityQueue
Enqueues a new element.- Specified by:
enqueue
in interfacePriorityQueue<K>
- Parameters:
x
- the element to enqueue.
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dequeue
public K dequeue()
Description copied from interface:PriorityQueue
Dequeues the first element from the queue.- Specified by:
dequeue
in interfacePriorityQueue<K>
- Returns:
- the dequeued element.
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first
public K first()
Description copied from interface:PriorityQueue
Returns the first element of the queue.- Specified by:
first
in interfacePriorityQueue<K>
- Returns:
- the first element.
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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<K>
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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<K>
- 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<K>
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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 Comparator<? super K> comparator()
Description copied from interface:PriorityQueue
Returns the comparator associated with this queue, ornull
if it uses its elements' natural ordering.- Specified by:
comparator
in interfacePriorityQueue<K>
- Returns:
- the comparator associated with this sorted set, or
null
if it uses its elements' natural ordering.
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