DoubleHeapSemiIndirectPriorityQueue (fastutil 6.4.1 API)

java.lang.Object
- it.unimi.dsi.fastutil.AbstractIndirectPriorityQueue<Double>
- - it.unimi.dsi.fastutil.doubles.DoubleHeapSemiIndirectPriorityQueue

All Implemented Interfaces:

IndirectPriorityQueue<Double>

Direct Known Subclasses:

DoubleHeapIndirectPriorityQueue
```
public class DoubleHeapSemiIndirectPriorityQueue
extends AbstractIndirectPriorityQueue<Double>
```
A type-specific heap-based semi-indirect priority queue.
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.
This implementation allows one to enqueue several time the same index, but you must be careful when calling changed().

Field Summary

Fields
Modifier and Type	Field and Description
`protected DoubleComparator`	`c` The type-specific comparator used in this queue.
`protected int[]`	`heap` The semi-indirect heap.
`protected double[]`	`refArray` The reference array.
`protected int`	`size` The number of elements in this queue.

Constructor Summary

Constructors
Constructor and Description
`DoubleHeapSemiIndirectPriorityQueue(double[] refArray)` Creates a new empty queue with capacity equal to the length of the reference array and using the natural order.
`DoubleHeapSemiIndirectPriorityQueue(double[] refArray, DoubleComparator c)` Creates a new empty queue with capacity equal to the length of the reference array and a given comparator.
`DoubleHeapSemiIndirectPriorityQueue(double[] refArray, int capacity)` Creates a new empty queue with given capacity and using the natural order.
`DoubleHeapSemiIndirectPriorityQueue(double[] refArray, int[] a)` Wraps a given array in a queue using the natural order.
`DoubleHeapSemiIndirectPriorityQueue(double[] refArray, int[] a, DoubleComparator c)` Wraps a given array in a queue using a given comparator.
`DoubleHeapSemiIndirectPriorityQueue(double[] refArray, int[] a, int size)` Wraps a given array in a queue using the natural order.
`DoubleHeapSemiIndirectPriorityQueue(double[] refArray, int[] a, int size, DoubleComparator c)` Wraps a given array in a queue using a given comparator.
`DoubleHeapSemiIndirectPriorityQueue(double[] refArray, int capacity, DoubleComparator c)` Creates a new empty queue without elements with a given capacity and comparator.

Method Summary

Methods
Modifier and Type	Method and Description
`void`	`allChanged()` Rebuilds this heap in a bottom-up fashion.
`void`	`changed()` Notifies this 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 queue, or `null` if it uses its elements' natural ordering.
`int`	`dequeue()` Dequeues the first element from this queue.
`void`	`enqueue(int x)` Enqueues a new element.
`protected void`	`ensureElement(int index)` Ensures that the given index is a valid reference.
`int`	`first()` Returns the first element of this queue.
`int`	`front(int[] a)` Retrieves the front of this queue in a given array (optional operation).
`int`	`size()` Returns the number of elements in this queue.
`String`	`toString()`
`void`	`trim()` Trims the backing array so that it has exactly `size()` elements.

Methods inherited from class it.unimi.dsi.fastutil.AbstractIndirectPriorityQueue
changed, contains, isEmpty, last, remove

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

- Field Detail
  - refArray
```
protected double[] refArray
```
    The reference array.
  - heap
```
protected int[] heap
```
    The semi-indirect heap.
  - size
```
protected int size
```
    The number of elements in this queue.
  - c
```
protected DoubleComparator c
```
    The type-specific comparator used in this queue.
- Constructor Detail
  - DoubleHeapSemiIndirectPriorityQueue
```
public DoubleHeapSemiIndirectPriorityQueue(double[] refArray,
                                   int capacity,
                                   DoubleComparator c)
```
    Creates a new empty queue without elements with a given capacity and comparator.
    
    Parameters:
    refArray - the reference array.
    capacity - the initial capacity of this queue.
    c - the comparator used in this queue, or null for the natural order.
  - DoubleHeapSemiIndirectPriorityQueue
```
public DoubleHeapSemiIndirectPriorityQueue(double[] refArray,
                                   int capacity)
```
    Creates a new empty queue with given capacity and using the natural order.
    
    Parameters:
    refArray - the reference array.
    capacity - the initial capacity of this queue.
  - DoubleHeapSemiIndirectPriorityQueue
```
public DoubleHeapSemiIndirectPriorityQueue(double[] refArray,
                                   DoubleComparator c)
```
    Creates a new empty queue with capacity equal to the length of the reference array and a given comparator.
    
    Parameters:
    refArray - the reference array.
    c - the comparator used in this queue, or null for the natural order.
  - DoubleHeapSemiIndirectPriorityQueue
```
public DoubleHeapSemiIndirectPriorityQueue(double[] refArray)
```
    Creates a new empty queue with capacity equal to the length of the reference array and using the natural order.
    
    Parameters:
    refArray - the reference array.
  - DoubleHeapSemiIndirectPriorityQueue
```
public DoubleHeapSemiIndirectPriorityQueue(double[] refArray,
                                   int[] 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 of a one by one).
    
    Parameters:
    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.
  - DoubleHeapSemiIndirectPriorityQueue
```
public DoubleHeapSemiIndirectPriorityQueue(double[] refArray,
                                   int[] 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:
    refArray - the reference array.
    a - an array of indices into refArray.
    c - the comparator used in this queue, or null for the natural order.
  - DoubleHeapSemiIndirectPriorityQueue
```
public DoubleHeapSemiIndirectPriorityQueue(double[] refArray,
                                   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. 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).
    
    Parameters:
    refArray - the reference array.
    a - an array of indices into refArray.
    size - the number of elements to be included in the queue.
  - DoubleHeapSemiIndirectPriorityQueue
```
public DoubleHeapSemiIndirectPriorityQueue(double[] refArray,
                                   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. 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:
    refArray - the reference array.
    a - an array of indices into refArray.
- Method Detail
  - ensureElement
```
protected void ensureElement(int index)
```
    Ensures that the given index is a valid reference.
    
    Parameters:
    index - an index in the reference array.
    
    Throws:
    
    IndexOutOfBoundsException - if the given index is negative or larger than the reference array length.
  - enqueue
```
public void enqueue(int x)
```
    Description copied from interface: IndirectPriorityQueue
    
    Enqueues a new element.
    
    Parameters:
    x - the element to enqueue..
  - dequeue
```
public int dequeue()
```
    Description copied from interface: IndirectPriorityQueue
    
    Dequeues the first element from this queue.
    
    Returns:
    the dequeued element.
  - first
```
public int first()
```
    Description copied from interface: IndirectPriorityQueue
    
    Returns the first element of this queue.
    
    Returns:
    the first element.
  - changed
```
public void changed()
```
    Notifies this queue that the first element has changed (optional operation).
    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.
    
    Specified by:
    
    changed in interface IndirectPriorityQueue<Double>
    
    Overrides:
    
    changed in class AbstractIndirectPriorityQueue<Double>
  - allChanged
```
public void allChanged()
```
    Rebuilds this heap in a bottom-up fashion.
    
    Specified by:
    
    allChanged in interface IndirectPriorityQueue<Double>
    
    Overrides:
    
    allChanged in class AbstractIndirectPriorityQueue<Double>
  - size
```
public int size()
```
    Description copied from interface: IndirectPriorityQueue
    
    Returns the number of elements in this queue.
    
    Returns:
    the number of elements in this queue.
  - clear
```
public void clear()
```
    Description copied from interface: IndirectPriorityQueue
    
    Removes all elements from this queue.
  - trim
```
public void trim()
```
    Trims the backing array so that it has exactly size() elements.
  - comparator
```
public DoubleComparator comparator()
```
    Description copied from interface: IndirectPriorityQueue
    
    Returns the comparator associated with this queue, or null if it uses its elements' natural ordering.
    
    Returns:
    the comparator associated with this sorted set, or null if it uses its elements' natural ordering.
  - front
```
public int front(int[] a)
```
    Description copied from interface: IndirectPriorityQueue
    
    Retrieves the front of this queue in a given array (optional operation).
    The front of an indirect queue is the set of indices whose associated elements in the reference array are equal to the element associated to the first index. These indices can be always obtain by dequeueing, but this method should retrieve efficiently such indices in the given array without modifying the state of this queue.
    
    Parameters:
    a - an array large enough to hold the front (e.g., at least long as the reference array).
    
    Returns:
    the number of elements actually written (starting from the first position of a).
  - toString
```
public String toString()
```
    Overrides:
    
    toString in class Object

Class DoubleHeapSemiIndirectPriorityQueue

Field Summary

Constructor Summary

Method Summary

Methods inherited from class it.unimi.dsi.fastutil.AbstractIndirectPriorityQueue

Methods inherited from class java.lang.Object

Field Detail

refArray

heap

size

c

Constructor Detail

DoubleHeapSemiIndirectPriorityQueue

DoubleHeapSemiIndirectPriorityQueue

DoubleHeapSemiIndirectPriorityQueue

DoubleHeapSemiIndirectPriorityQueue

DoubleHeapSemiIndirectPriorityQueue

DoubleHeapSemiIndirectPriorityQueue

DoubleHeapSemiIndirectPriorityQueue

DoubleHeapSemiIndirectPriorityQueue

Method Detail

ensureElement

enqueue

dequeue

first

changed

allChanged

size

clear

trim

comparator

front

toString