Package net.cscott.jutil

Class FibonacciHeap<K,V>

java.lang.Object
net.cscott.jutil.AbstractHeap<K,V>
net.cscott.jutil.FibonacciHeap<K,V>
All Implemented Interfaces:
Iterable<Map.Entry<K,V>>, Heap<K,V>
public class FibonacciHeap<K,V> extends AbstractHeap<K,V>
A FibonacciHeap allows amortized O(1) time bounds for create, insert, minimum, union, and decrease-key operations, and amortized O(lg n) run times for extract-min and delete.

Implementation is based on the description in Introduction to Algorithms by Cormen, Leiserson, and Riverst, in Chapter 21.

Author:
C. Scott Ananian <cananian@alumni.princeton.edu>

  • Constructor Details

    • FibonacciHeap

      public FibonacciHeap()
      Creates a new, empty FibonacciHeap, sorted according to its keys' natural order. All keys inserted into the new map must implement the Comparable interface. O(1) time.

    • FibonacciHeap

      public FibonacciHeap(Comparator<? super K> c)
      Creates a new, empty FibonacciHeap, sorted according to the given Comparator. O(1) time.

    • FibonacciHeap

      public FibonacciHeap(Heap<K,? extends V> h)
      Constructs a new heap with the same entries as the specified Heap. O(n) time.

    • FibonacciHeap

      public FibonacciHeap(Collection<? extends Map.Entry<? extends K,? extends V>> collection, Comparator<? super K> comparator)
      Constructs a new heap from a collection of Map.Entrys and a key comparator. O(n) time.

  • Method Details

    • insert

      public Map.Entry<K,V> insert(K key, V value)
      Insert an entry into the heap.
      Specified by:
      insert in interface Heap<K,V>
      Specified by:
      insert in class AbstractHeap<K,V>

    • insert

      protected void insert(Map.Entry<K,V> me)
      Description copied from class: AbstractHeap
      This method should insert the specified Map.Entry, which is not currently in the Heap, into the Heap. Implementation is optional, but it is required if you use the default implementation of updateKey().
      Overrides:
      insert in class AbstractHeap<K,V>

    • minimum

      public Map.Entry<K,V> minimum()
      Description copied from interface: Heap
      Returns a mapping entry with minimal key.
      Specified by:
      minimum in interface Heap<K,V>
      Specified by:
      minimum in class AbstractHeap<K,V>

    • union

      public void union(FibonacciHeap<K,V> h)

    • union

      public void union(Heap<? extends K,? extends V> h)
      Description copied from interface: Heap
      Merges all of the mappings from the specified Heap into this Heap. Note that duplicates are permitted. After calling union(), the Heap passed in as an argument will be empty.

      Note that usually efficient implementations of this method require that the Heap argument be from the same implementation as this. (That is, they must both be binomial heaps, or both fibonacci heaps, etc.)

      Specified by:
      union in interface Heap<K,V>
      Overrides:
      union in class AbstractHeap<K,V>

    • extractMinimum

      public Map.Entry<K,V> extractMinimum()
      Description copied from interface: Heap
      Remove and return a map entry with minimal key.
      Specified by:
      extractMinimum in interface Heap<K,V>
      Overrides:
      extractMinimum in class AbstractHeap<K,V>

    • decreaseKey

      public void decreaseKey(Map.Entry<K,V> me, K newkey)
      Description copied from interface: Heap
      Replace the key in the specified map entry with the specified smaller key.
      Specified by:
      decreaseKey in interface Heap<K,V>
      Specified by:
      decreaseKey in class AbstractHeap<K,V>

    • delete

      public void delete(Map.Entry<K,V> me)
      Description copied from interface: Heap
      Remove the specified map entry from the mapping.
      Specified by:
      delete in interface Heap<K,V>
      Specified by:
      delete in class AbstractHeap<K,V>

    • size

      public int size()
      Description copied from interface: Heap
      Returns the number of entries in this Heap.
      Specified by:
      size in interface Heap<K,V>
      Specified by:
      size in class AbstractHeap<K,V>

    • clear

      public void clear()
      Description copied from interface: Heap
      Removes all entries from this Heap.
      Specified by:
      clear in interface Heap<K,V>
      Specified by:
      clear in class AbstractHeap<K,V>

    • entries

      public Collection<Map.Entry<K,V>> entries()
      Description copied from interface: Heap
      Returns a collection view of all the Map.Entrys in this Heap.
      Specified by:
      entries in interface Heap<K,V>
      Specified by:
      entries in class AbstractHeap<K,V>

    • setKey

      protected final K setKey(Map.Entry<K,V> me, K newkey)
      Description copied from class: AbstractHeap
      This method should set the key for the specified Map.Entry to the given newkey. Implementation is optional, but it is required if you use the default implementation of updateKey().
      Overrides:
      setKey in class AbstractHeap<K,V>