it.unimi.dsi.fastutil.chars
Class CharHeapSemiIndirectPriorityQueue

java.lang.Object
  extended byit.unimi.dsi.fastutil.AbstractIndirectPriorityQueue
      extended byit.unimi.dsi.fastutil.chars.CharHeapSemiIndirectPriorityQueue
All Implemented Interfaces:
IndirectPriorityQueue
Direct Known Subclasses:
CharHeapIndirectPriorityQueue, CharHeapSesquiIndirectDoublePriorityQueue

public class CharHeapSemiIndirectPriorityQueue
extends AbstractIndirectPriorityQueue

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().


Constructor Summary
CharHeapSemiIndirectPriorityQueue(char[] refArray)
          Creates a new empty queue with capacity equal to the length of the reference array and using the natural order.
CharHeapSemiIndirectPriorityQueue(char[] refArray, CharComparator c)
          Creates a new empty queue with capacity equal to the length of the reference array and a given comparator.
CharHeapSemiIndirectPriorityQueue(char[] refArray, int capacity)
          Creates a new empty queue with given capacity and using the natural order.
CharHeapSemiIndirectPriorityQueue(char[] refArray, int[] a)
          Wraps a given array in a queue using the natural order.
CharHeapSemiIndirectPriorityQueue(char[] refArray, int[] a, CharComparator c)
          Wraps a given array in a queue using a given comparator.
CharHeapSemiIndirectPriorityQueue(char[] refArray, int[] a, int size)
          Wraps a given array in a queue using the natural order.
CharHeapSemiIndirectPriorityQueue(char[] refArray, int[] a, int size, CharComparator c)
          Wraps a given array in a queue using a given comparator.
CharHeapSemiIndirectPriorityQueue(char[] refArray, int capacity, CharComparator c)
          Creates a new empty queue without elements with a given capacity and comparator.
 
Method Summary
 void allChanged()
          Rebuilds this heap in a bottom-up fashion.
 void changed()
           The caller must guarantee that when this method is called the index of the first element appears just once in the queue.
 void clear()
          Removes all elements from this queue.
 Comparator comparator()
          Returns the comparator associated with this queue, or null if it uses its elements' natural ordering.
 int dequeue()
          Dequeues the first element from the queue.
 void enqueue(int x)
          Enqueues a new element.
 int first()
          Returns the first element of the queue.
 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, isEmpty, last, remove
 
Methods inherited from class java.lang.Object
equals, getClass, hashCode, notify, notifyAll, wait, wait, wait
 

Constructor Detail

CharHeapSemiIndirectPriorityQueue

public CharHeapSemiIndirectPriorityQueue(char[] refArray,
                                         int capacity,
                                         CharComparator 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.

CharHeapSemiIndirectPriorityQueue

public CharHeapSemiIndirectPriorityQueue(char[] 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.

CharHeapSemiIndirectPriorityQueue

public CharHeapSemiIndirectPriorityQueue(char[] refArray,
                                         CharComparator 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.

CharHeapSemiIndirectPriorityQueue

public CharHeapSemiIndirectPriorityQueue(char[] 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.

CharHeapSemiIndirectPriorityQueue

public CharHeapSemiIndirectPriorityQueue(char[] refArray,
                                         int[] a,
                                         int size,
                                         CharComparator 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.

CharHeapSemiIndirectPriorityQueue

public CharHeapSemiIndirectPriorityQueue(char[] refArray,
                                         int[] a,
                                         CharComparator 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.

CharHeapSemiIndirectPriorityQueue

public CharHeapSemiIndirectPriorityQueue(char[] 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.

CharHeapSemiIndirectPriorityQueue

public CharHeapSemiIndirectPriorityQueue(char[] 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

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 the queue.

Returns:
the dequeued element.

first

public int first()
Description copied from interface: IndirectPriorityQueue
Returns the first element of the queue.

Returns:
the first element.

changed

public void changed()

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
Overrides:
changed in class AbstractIndirectPriorityQueue

allChanged

public void allChanged()
Rebuilds this heap in a bottom-up fashion.

Specified by:
allChanged in interface IndirectPriorityQueue
Overrides:
allChanged in class AbstractIndirectPriorityQueue

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 Comparator 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.

toString

public String toString()