Class IntArrayPriorityQueue
- java.lang.Object
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- it.unimi.dsi.fastutil.ints.IntArrayPriorityQueue
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- All Implemented Interfaces:
IntPriorityQueue
,PriorityQueue<Integer>
,Serializable
public class IntArrayPriorityQueue extends Object implements IntPriorityQueue, 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 IntArrayPriorityQueue()
Creates a new empty queue using the natural order.IntArrayPriorityQueue(int capacity)
Creates a new empty queue with a given capacity and using the natural order.IntArrayPriorityQueue(int[] a)
Wraps a given array in a queue using the natural order.IntArrayPriorityQueue(int[] a, int size)
Wraps a given array in a queue using the natural order.IntArrayPriorityQueue(int[] a, int size, IntComparator c)
Wraps a given array in a queue using a given comparator.IntArrayPriorityQueue(int[] a, IntComparator c)
Wraps a given array in a queue using a given comparator.IntArrayPriorityQueue(int capacity, IntComparator c)
Creates a new empty queue with a given capacity and comparator.IntArrayPriorityQueue(IntComparator 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.IntComparator
comparator()
Returns the comparator associated with this priority queue, or null if it uses its elements' natural ordering.int
dequeueInt()
Dequeues the first element from the queue.void
enqueue(int x)
Enqueues a new element.int
firstInt()
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.ints.IntPriorityQueue
dequeue, enqueue, first, last, lastInt
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Methods inherited from interface it.unimi.dsi.fastutil.PriorityQueue
isEmpty
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Constructor Detail
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IntArrayPriorityQueue
public IntArrayPriorityQueue(int capacity, IntComparator 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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IntArrayPriorityQueue
public IntArrayPriorityQueue(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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IntArrayPriorityQueue
public IntArrayPriorityQueue(IntComparator 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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IntArrayPriorityQueue
public IntArrayPriorityQueue()
Creates a new empty queue using the natural order.
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IntArrayPriorityQueue
public IntArrayPriorityQueue(int[] a, int size, IntComparator 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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IntArrayPriorityQueue
public IntArrayPriorityQueue(int[] a, IntComparator 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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IntArrayPriorityQueue
public IntArrayPriorityQueue(int[] 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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IntArrayPriorityQueue
public IntArrayPriorityQueue(int[] 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(int x)
Description copied from interface:IntPriorityQueue
Enqueues a new element.- Specified by:
enqueue
in interfaceIntPriorityQueue
- Parameters:
x
- the element to enqueue.- See Also:
PriorityQueue.enqueue(Object)
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dequeueInt
public int dequeueInt()
Description copied from interface:IntPriorityQueue
Dequeues the first element from the queue.- Specified by:
dequeueInt
in interfaceIntPriorityQueue
- Returns:
- the dequeued element.
- See Also:
IntPriorityQueue.dequeue()
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firstInt
public int firstInt()
Description copied from interface:IntPriorityQueue
Returns the first element of the queue.- Specified by:
firstInt
in interfaceIntPriorityQueue
- Returns:
- the first element.
- See Also:
IntPriorityQueue.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<Integer>
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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<Integer>
- 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<Integer>
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trim
public void trim()
Trims the underlying array so that it has exactlysize()
elements.
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comparator
public IntComparator comparator()
Description copied from interface:IntPriorityQueue
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 interfaceIntPriorityQueue
- Specified by:
comparator
in interfacePriorityQueue<Integer>
- Returns:
- the comparator associated with this priority queue.
- See Also:
PriorityQueue.comparator()
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