Package org.jheaps.tree

Class DaryTreeAddressableHeap<K,V>

java.lang.Object
org.jheaps.tree.DaryTreeAddressableHeap<K,V>
Type Parameters:
K - the type of keys maintained by this heap
V - the type of values maintained by this heap
All Implemented Interfaces:
Serializable, AddressableHeap<K,V>
public class DaryTreeAddressableHeap<K,V> extends Object implements AddressableHeap<K,V>, Serializable
An explicit d-ary tree addressable heap. The heap is sorted according to the natural ordering of its keys, or by a Comparator provided at heap creation time, depending on which constructor is used.

The worst-case cost of insert, deleteMin, delete and decreaceKey operations is O(d log_d(n)) and the cost of findMin is O(1).

Note that the ordering maintained by a binary heap, like any heap, and whether or not an explicit comparator is provided, must be consistent with equals if this heap is to correctly implement the Heap interface. (See Comparable or Comparator for a precise definition of consistent with equals.) This is so because the Heap interface is defined in terms of the equals operation, but a binary heap performs all key comparisons using its compareTo (or compare) method, so two keys that are deemed equal by this method are, from the standpoint of the binary heap, equal. The behavior of a heap is well-defined even if its ordering is inconsistent with equals; it just fails to obey the general contract of the Heap interface.

Note that this implementation is not synchronized. If multiple threads access a heap concurrently, and at least one of the threads modifies the heap structurally, it must be synchronized externally. (A structural modification is any operation that adds or deletes one or more elements or changing the key of some element.) This is typically accomplished by synchronizing on some object that naturally encapsulates the heap.

See Also:

  • Field Details

    • serialVersionUID

      private static final long serialVersionUID
      See Also:

    • comparator

      private final Comparator<? super K> comparator
      The comparator used to maintain order in this heap, or null if it uses the natural ordering of its keys.

    • size

      private long size
      Size of the heap

    • root

      private DaryTreeAddressableHeap<K,V>.Node root
      Root node of the heap

    • d

      private final int d
      Branching factor. Always a power of two.

    • log2d

      private final int log2d
      Base 2 logarithm of branching factor.

    • aux

      private DaryTreeAddressableHeap<K,V>.Node[] aux
      Auxiliary for swapping children.

  • Constructor Details

    • DaryTreeAddressableHeap

      public DaryTreeAddressableHeap(int d)
      Constructs a new, empty heap, using the natural ordering of its keys.

      All keys inserted into the heap must implement the Comparable interface. Furthermore, all such keys must be mutually comparable: k1.compareTo(k2) must not throw a ClassCastException for any keys k1 and k2 in the heap. If the user attempts to put a key into the heap that violates this constraint (for example, the user attempts to put a string key into a heap whose keys are integers), the insert(Object key) call will throw a ClassCastException.

      Parameters:
      d - the branching factor. Should be a power of 2.

    • DaryTreeAddressableHeap

      public DaryTreeAddressableHeap(int d, Comparator<? super K> comparator)
      Constructs a new, empty heap, ordered according to the given comparator.

      All keys inserted into the heap must be mutually comparable by the given comparator: comparator.compare(k1, k2) must not throw a ClassCastException for any keys k1 and k2 in the heap. If the user attempts to put a key into the heap that violates this constraint, the insert(Object key) call will throw a ClassCastException.

      Parameters:
      d - the branching factor. Should be a power of 2.
      comparator - the comparator that will be used to order this heap. If null, the natural ordering of the keys will be used.

  • Method Details