K - the type of keys maintained by this heapV - the type of values maintained by this heappublic class FibonacciHeap<K,V> extends Object implements MergeableAddressableHeap<K,V>, Serializable
Comparator provided at heap
creation time, depending on which constructor is used.
This implementation provides amortized O(1) time for operations that do not
involve deleting an element such as insert, and decreaseKey.
Operation findMin is worst-case O(1). Operations deleteMin
and delete are amortized O(log(n)). The operation meld is
also amortized O(1).
All the above bounds, however, assume that the user does not perform cascading melds on heaps such as:
d.meld(e); c.meld(d); b.meld(c); a.meld(b);The above scenario, although efficiently supported by using union-find with path compression, invalidates the claimed bounds.
Note that the ordering maintained by a Fibonacci 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
AddressableHeap interface. (See Comparable or
Comparator for a precise definition of consistent with
equals.) This is so because the AddressableHeap interface is
defined in terms of the equals operation, but a Fibonacci 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 Fibonacci 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 AddressableHeap
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.
PairingHeap,
CostlessMeldPairingHeap,
Serialized FormAddressableHeap.Handle<K,V>| Constructor and Description |
|---|
FibonacciHeap()
Constructs a new, empty heap, using the natural ordering of its keys.
|
FibonacciHeap(Comparator<? super K> comparator)
Constructs a new, empty heap, ordered according to the given comparator.
|
| Modifier and Type | Method and Description |
|---|---|
void |
clear()
Clear all the elements of the heap.
|
Comparator<? super K> |
comparator()
Returns the comparator used to order the keys in this AddressableHeap, or
null if this heap uses the natural
ordering of its keys. |
AddressableHeap.Handle<K,V> |
deleteMin()
Delete and return an element with the minimum key.
|
AddressableHeap.Handle<K,V> |
findMin()
Find an element with the minimum key.
|
AddressableHeap.Handle<K,V> |
insert(K key)
Insert a new element into the heap with a null value.
|
AddressableHeap.Handle<K,V> |
insert(K key,
V value)
Insert a new element into the heap.
|
boolean |
isEmpty()
Returns
true if this heap is empty. |
void |
meld(MergeableAddressableHeap<K,V> other)
Meld a heap into the current heap.
|
long |
size()
Returns the number of elements in the heap.
|
public FibonacciHeap()
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.public FibonacciHeap(Comparator<? super K> 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.comparator - the comparator that will be used to order this heap. If
null, the natural ordering of
the keys will be used.public AddressableHeap.Handle<K,V> insert(K key, V value)
insert in interface AddressableHeap<K,V>key - the element's keyvalue - the element's valueIllegalStateException - if the heap has already been used in the right hand side of a
meldpublic AddressableHeap.Handle<K,V> insert(K key)
insert in interface AddressableHeap<K,V>key - the element's keyIllegalStateException - if the heap has already been used in the right hand side of a
meldpublic AddressableHeap.Handle<K,V> findMin()
findMin in interface AddressableHeap<K,V>public AddressableHeap.Handle<K,V> deleteMin()
AddressableHeap.Handle.getKey()
and AddressableHeap.Handle.getValue() can be used.deleteMin in interface AddressableHeap<K,V>public boolean isEmpty()
true if this heap is empty.isEmpty in interface AddressableHeap<K,V>true if this heap is empty, false otherwisepublic long size()
size in interface AddressableHeap<K,V>public Comparator<? super K> comparator()
null if this heap uses the natural
ordering of its keys.comparator in interface AddressableHeap<K,V>null if this addressable heap uses the natural ordering
of its keyspublic void clear()
AddressableHeap.Handle.decreaseKey(Object) and AddressableHeap.Handle.delete() is
undefined.clear in interface AddressableHeap<K,V>public void meld(MergeableAddressableHeap<K,V> other)
other heap will be empty and will not
permit further insertions.meld in interface MergeableAddressableHeap<K,V>other - a merge-able heapCopyright © 2018. All rights reserved.