K - the type of keys maintained by this heapV - the type of values maintained by this heappublic class ReflectedHeap<K,V> extends Object implements MergeableDoubleEndedAddressableHeap<K,V>, Serializable
Comparator provided at heap creation time, depending on which
constructor is used.
This class implements a general technique which uses two
MergeableAddressableHeaps to implement a double ended heap, described
in detail in the following
paper:
The running time bounds depend on the implementation of the underlying used heap. 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 this 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 this 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
this 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.
DoubleEndedAddressableHeap.Handle<K,V>| Constructor and Description |
|---|
ReflectedHeap(AddressableHeapFactory<K,?> heapFactory)
Constructs a new, empty heap, using the natural ordering of its keys.
|
ReflectedHeap(AddressableHeapFactory<K,?> heapFactory,
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. |
DoubleEndedAddressableHeap.Handle<K,V> |
deleteMax()
Delete and return an element with the maximum key.
|
DoubleEndedAddressableHeap.Handle<K,V> |
deleteMin()
Delete and return an element with the minimum key.
|
DoubleEndedAddressableHeap.Handle<K,V> |
findMax()
Find an element with the maximum key.
|
DoubleEndedAddressableHeap.Handle<K,V> |
findMin()
Find an element with the minimum key.
|
DoubleEndedAddressableHeap.Handle<K,V> |
insert(K key)
Insert a new element into the heap with a null value.
|
DoubleEndedAddressableHeap.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(MergeableDoubleEndedAddressableHeap<K,V> other)
Meld a heap into the current heap.
|
long |
size()
Returns the number of elements in the heap.
|
public ReflectedHeap(AddressableHeapFactory<K,?> heapFactory)
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.heapFactory - a factory for the underlying heap implementationNullPointerException - if the heap factory is nullpublic ReflectedHeap(AddressableHeapFactory<K,?> heapFactory, 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.heapFactory - a factory for the underlying heap implementationcomparator - the comparator that will be used to order this heap. If
null, the natural ordering of
the keys will be used.NullPointerException - if the heap factory is nullpublic 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 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 void clear()
AddressableHeap.Handle.decreaseKey(Object) and AddressableHeap.Handle.delete() is
undefined.clear in interface AddressableHeap<K,V>public DoubleEndedAddressableHeap.Handle<K,V> insert(K key, V value)
insert in interface AddressableHeap<K,V>insert in interface DoubleEndedAddressableHeap<K,V>key - the element's keyvalue - the element's valuepublic DoubleEndedAddressableHeap.Handle<K,V> insert(K key)
insert in interface AddressableHeap<K,V>insert in interface DoubleEndedAddressableHeap<K,V>key - the element's keypublic DoubleEndedAddressableHeap.Handle<K,V> findMin()
findMin in interface AddressableHeap<K,V>findMin in interface DoubleEndedAddressableHeap<K,V>public DoubleEndedAddressableHeap.Handle<K,V> findMax()
findMax in interface DoubleEndedAddressableHeap<K,V>public DoubleEndedAddressableHeap.Handle<K,V> deleteMin()
AddressableHeap.Handle.getKey()
and AddressableHeap.Handle.getValue() can be used.deleteMin in interface AddressableHeap<K,V>deleteMin in interface DoubleEndedAddressableHeap<K,V>public DoubleEndedAddressableHeap.Handle<K,V> deleteMax()
deleteMax in interface DoubleEndedAddressableHeap<K,V>public void meld(MergeableDoubleEndedAddressableHeap<K,V> other)
other heap will be empty and will not
permit further insertions.meld in interface MergeableDoubleEndedAddressableHeap<K,V>other - a merge-able heapCopyright © 2018. All rights reserved.