Package it.unimi.dsi.fastutil.bytes

Class ByteHeapSemiIndirectPriorityQueue

java.lang.Object
it.unimi.dsi.fastutil.bytes.ByteHeapSemiIndirectPriorityQueue
All Implemented Interfaces:
ByteIndirectPriorityQueue, it.unimi.dsi.fastutil.IndirectPriorityQueue<java.lang.Byte>
Direct Known Subclasses:
ByteHeapIndirectPriorityQueue
public class ByteHeapSemiIndirectPriorityQueue
extends java.lang.Object
implements ByteIndirectPriorityQueue
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.

Implementation Specification:
This implementation allows one to enqueue several time the same index, but you must be careful when calling changed().

  • Constructor Summary

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

  • Method Summary

    Modifier and Type Method Description
    void allChanged()
    Rebuilds this heap in a bottom-up fashion (in linear time).
    void changed()
    void clear()  
    ByteComparator comparator()
    Returns the type-specific comparator associated with this queue.
    int dequeue()  
    void enqueue​(int x)  
    int first()  
    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.
    int size()  
    java.lang.String toString()  
    void trim()
    Trims the backing array so that it has exactly size() elements.

    Methods inherited from class java.lang.Object

    equals, getClass, hashCode, notify, notifyAll, wait, wait, wait

    Methods inherited from interface it.unimi.dsi.fastutil.IndirectPriorityQueue

    changed, contains, isEmpty, last, remove

  • Constructor Details

    • ByteHeapSemiIndirectPriorityQueue

      public ByteHeapSemiIndirectPriorityQueue​(byte[] refArray, int capacity, ByteComparator 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.

    • ByteHeapSemiIndirectPriorityQueue

      public ByteHeapSemiIndirectPriorityQueue​(byte[] 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.

    • ByteHeapSemiIndirectPriorityQueue

      public ByteHeapSemiIndirectPriorityQueue​(byte[] refArray, ByteComparator 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.

    • ByteHeapSemiIndirectPriorityQueue

      public ByteHeapSemiIndirectPriorityQueue​(byte[] 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.

    • ByteHeapSemiIndirectPriorityQueue

      public ByteHeapSemiIndirectPriorityQueue​(byte[] refArray, int[] a, int size, ByteComparator 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.

    • ByteHeapSemiIndirectPriorityQueue

      public ByteHeapSemiIndirectPriorityQueue​(byte[] refArray, int[] a, ByteComparator 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.

    • ByteHeapSemiIndirectPriorityQueue

      public ByteHeapSemiIndirectPriorityQueue​(byte[] 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.

    • ByteHeapSemiIndirectPriorityQueue

      public ByteHeapSemiIndirectPriorityQueue​(byte[] 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 Details

    • enqueue

      public void enqueue​(int x)
      Specified by:
      enqueue in interface it.unimi.dsi.fastutil.IndirectPriorityQueue<java.lang.Byte>

    • dequeue

      public int dequeue()
      Specified by:
      dequeue in interface it.unimi.dsi.fastutil.IndirectPriorityQueue<java.lang.Byte>

    • first

      public int first()
      Specified by:
      first in interface it.unimi.dsi.fastutil.IndirectPriorityQueue<java.lang.Byte>

    • 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 it.unimi.dsi.fastutil.IndirectPriorityQueue<java.lang.Byte>

    • allChanged

      public void allChanged()
      Rebuilds this heap in a bottom-up fashion (in linear time).
      Specified by:
      allChanged in interface it.unimi.dsi.fastutil.IndirectPriorityQueue<java.lang.Byte>

    • size

      public int size()
      Specified by:
      size in interface it.unimi.dsi.fastutil.IndirectPriorityQueue<java.lang.Byte>

    • clear

      public void clear()
      Specified by:
      clear in interface it.unimi.dsi.fastutil.IndirectPriorityQueue<java.lang.Byte>

    • trim

      public void trim()
      Trims the backing array so that it has exactly size() elements.

    • comparator

      public ByteComparator comparator()
      Description copied from interface: ByteIndirectPriorityQueue
      Returns the type-specific comparator associated with this queue.
      Specified by:
      comparator in interface ByteIndirectPriorityQueue
      Specified by:
      comparator in interface it.unimi.dsi.fastutil.IndirectPriorityQueue<java.lang.Byte>
      Returns:
      the comparator associated with this queue.
      See Also:
      IndirectPriorityQueue.comparator()

    • front

      public 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.
      Specified by:
      front in interface it.unimi.dsi.fastutil.IndirectPriorityQueue<java.lang.Byte>
      Parameters:
      a - an array whose initial part will be filled with the frnot (must be sized as least as the heap size).
      Returns:
      the number of elements of the front.

    • toString

      public java.lang.String toString()
      Overrides:
      toString in class java.lang.Object