public class ByteHeapSemiIndirectPriorityQueue extends java.lang.Object implements ByteIndirectPriorityQueue
Instances of this class use as reference list a reference array,
which must be provided to each constructor. The priority queue is
represented using a heap. The heap is enlarged as needed, but it is never
shrunk. Use the trim()
method to reduce its size, if necessary.
changed()
.Constructor and Description |
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ByteHeapSemiIndirectPriorityQueue(byte[] refArray)
Creates a new empty queue with capacity equal to the length of the reference array and using the natural order.
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ByteHeapSemiIndirectPriorityQueue(byte[] refArray,
ByteComparator c)
Creates a new empty queue with capacity equal to the length of the reference array and a given comparator.
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ByteHeapSemiIndirectPriorityQueue(byte[] refArray,
int capacity)
Creates a new empty queue with given capacity and using the natural order.
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ByteHeapSemiIndirectPriorityQueue(byte[] refArray,
int[] a)
Wraps a given array in a queue using the natural order.
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ByteHeapSemiIndirectPriorityQueue(byte[] refArray,
int[] a,
ByteComparator c)
Wraps a given array in a queue using a given comparator.
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ByteHeapSemiIndirectPriorityQueue(byte[] refArray,
int[] a,
int size)
Wraps a given array in a queue using the natural order.
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ByteHeapSemiIndirectPriorityQueue(byte[] refArray,
int[] a,
int size,
ByteComparator c)
Wraps a given array in a queue using a given comparator.
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ByteHeapSemiIndirectPriorityQueue(byte[] refArray,
int capacity,
ByteComparator c)
Creates a new empty queue without elements with a given capacity and comparator.
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Modifier and Type | Method and Description |
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void |
allChanged()
Rebuilds this heap in a bottom-up fashion (in linear time).
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void |
changed()
Notifies this queue that the first element has changed (optional operation).
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void |
clear()
Removes all elements from this queue.
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ByteComparator |
comparator()
Returns the type-specific comparator associated with this queue.
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int |
dequeue()
Dequeues the first element from this queue.
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void |
enqueue(int x)
Enqueues a new element.
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int |
first()
Returns the first element of this queue.
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int |
front(int[] a)
Writes in the provided array the front of the queue, that is, the set of indices
whose elements have the same priority as the top.
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int |
size()
Returns the number of elements in this queue.
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java.lang.String |
toString() |
void |
trim()
Trims the backing array so that it has exactly
size() elements. |
public ByteHeapSemiIndirectPriorityQueue(byte[] refArray, int capacity, ByteComparator c)
refArray
- the reference array.capacity
- the initial capacity of this queue.c
- the comparator used in this queue, or null
for the natural order.public ByteHeapSemiIndirectPriorityQueue(byte[] refArray, int capacity)
refArray
- the reference array.capacity
- the initial capacity of this queue.public ByteHeapSemiIndirectPriorityQueue(byte[] refArray, ByteComparator c)
refArray
- the reference array.c
- the comparator used in this queue, or null
for the natural order.public ByteHeapSemiIndirectPriorityQueue(byte[] refArray)
refArray
- the reference array.public ByteHeapSemiIndirectPriorityQueue(byte[] refArray, int[] a, int size, ByteComparator c)
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 of a
one by one).
refArray
- the reference array.a
- an array of indices into refArray
.size
- the number of elements to be included in the queue.c
- the comparator used in this queue, or null
for the natural order.public ByteHeapSemiIndirectPriorityQueue(byte[] refArray, int[] a, ByteComparator c)
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).
refArray
- the reference array.a
- an array of indices into refArray
.c
- the comparator used in this queue, or null
for the natural order.public ByteHeapSemiIndirectPriorityQueue(byte[] refArray, int[] a, int size)
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 of a
one by one).
refArray
- the reference array.a
- an array of indices into refArray
.size
- the number of elements to be included in the queue.public ByteHeapSemiIndirectPriorityQueue(byte[] refArray, int[] a)
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).
refArray
- the reference array.a
- an array of indices into refArray
.public void enqueue(int x)
IndirectPriorityQueue
enqueue
in interface IndirectPriorityQueue<java.lang.Byte>
x
- the element to enqueue.public int dequeue()
IndirectPriorityQueue
dequeue
in interface IndirectPriorityQueue<java.lang.Byte>
public int first()
IndirectPriorityQueue
first
in interface IndirectPriorityQueue<java.lang.Byte>
public void changed()
This default implementation just calls IndirectPriorityQueue.changed(int)
with argument IndirectPriorityQueue.first()
.
The caller must guarantee that when this method is called the index of the first element appears just once in the queue. Failure to do so will bring the queue in an inconsistent state, and will cause unpredictable behaviour.
changed
in interface IndirectPriorityQueue<java.lang.Byte>
public void allChanged()
allChanged
in interface IndirectPriorityQueue<java.lang.Byte>
public int size()
IndirectPriorityQueue
size
in interface IndirectPriorityQueue<java.lang.Byte>
public void clear()
IndirectPriorityQueue
clear
in interface IndirectPriorityQueue<java.lang.Byte>
public void trim()
size()
elements.public ByteComparator comparator()
ByteIndirectPriorityQueue
comparator
in interface ByteIndirectPriorityQueue
comparator
in interface IndirectPriorityQueue<java.lang.Byte>
IndirectPriorityQueue.comparator()
public int front(int[] a)
front
in interface IndirectPriorityQueue<java.lang.Byte>
a
- an array whose initial part will be filled with the frnot (must be sized as least as the heap size).public java.lang.String toString()
toString
in class java.lang.Object