Package it.unimi.dsi.fastutil.ints
Class IntArrayFIFOQueue
java.lang.Object
it.unimi.dsi.fastutil.ints.IntArrayFIFOQueue
- All Implemented Interfaces:
IntPriorityQueue
,PriorityQueue<Integer>
,Serializable
A type-specific array-based FIFO queue, supporting also deque operations.
Instances of this class represent a FIFO queue using a backing array in a circular way. The array
is enlarged and shrunk as needed. You can use the trim()
method to reduce its memory
usage, if necessary.
This class provides additional methods that implement a deque (double-ended queue).
- See Also:
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Field Summary
Modifier and TypeFieldDescriptionstatic final int
The standard initial capacity of a queue. -
Constructor Summary
ConstructorDescriptionCreates a new empty queue with standard initial capacity.IntArrayFIFOQueue
(int capacity) Creates a new empty queue with given capacity. -
Method Summary
Modifier and TypeMethodDescriptionvoid
clear()
Removes all elements from this queue.Returns the comparator associated with this priority queue, or null if it uses its elements' natural ordering.int
Dequeues the first element from the queue.int
Dequeues the last element from the queue.void
enqueue
(int x) Enqueues a new element.void
enqueueFirst
(int x) Enqueues a new element as the first element (in dequeuing order) of the queue.int
firstInt()
Returns the first element of the queue.int
lastInt()
Returns the last element of the queue, that is, the element the would be dequeued last (optional operation).int
size()
Returns the number of elements in this queue.void
trim()
Trims the queue to the smallest possible size.Methods inherited from class java.lang.Object
equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
Methods inherited from interface it.unimi.dsi.fastutil.ints.IntPriorityQueue
dequeue, enqueue, first, last
Methods inherited from interface it.unimi.dsi.fastutil.PriorityQueue
changed, isEmpty
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Field Details
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INITIAL_CAPACITY
public static final int INITIAL_CAPACITYThe standard initial capacity of a queue.- See Also:
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Constructor Details
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IntArrayFIFOQueue
public IntArrayFIFOQueue(int capacity) Creates a new empty queue with given capacity.- Parameters:
capacity
- the initial capacity of this queue.- Implementation Notes:
- Because of inner limitations of the JVM, the initial capacity cannot exceed
Arrays.MAX_ARRAY_SIZE
− 1.
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IntArrayFIFOQueue
public IntArrayFIFOQueue()Creates a new empty queue with standard initial capacity.
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Method Details
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comparator
Returns the comparator associated with this priority queue, or null if it uses its elements' natural ordering.- Specified by:
comparator
in interfaceIntPriorityQueue
- Specified by:
comparator
in interfacePriorityQueue<Integer>
- Returns:
- the comparator associated with this priority queue.
- See Also:
- Implementation Specification:
- This implementation returns
null
(FIFO queues have no comparator).
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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:
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dequeueLastInt
public int dequeueLastInt()Dequeues the last element from the queue.- Returns:
- the dequeued element.
- Throws:
NoSuchElementException
- if the queue is empty.
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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:
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enqueueFirst
public void enqueueFirst(int x) Enqueues a new element as the first element (in dequeuing order) of the queue.- Parameters:
x
- the element to enqueue.
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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:
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lastInt
public int lastInt()Description copied from interface:IntPriorityQueue
Returns the last element of the queue, that is, the element the would be dequeued last (optional operation).This default implementation just throws an
UnsupportedOperationException
.- Specified by:
lastInt
in interfaceIntPriorityQueue
- Returns:
- the last element.
- See Also:
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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 queue to the smallest possible size. -
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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