K - the type of keys maintained by this heapV - the type of values maintained by this heappublic class SkewHeap<K,V> extends Object implements MergeableAddressableHeap<K,V>, Serializable
Comparator provided at heap
creation time, depending on which constructor is used.
Operations insert, deleteMin, and delete take
amortized O(log(n)). Operation findMin is worst-case O(1). Note that
a skew-heap does not efficiently support the operation decreaseKey
which is amortized Ω(log(n)).
Note that the ordering maintained by 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 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 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
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.
AddressableHeap.Handle<K,V>| Constructor and Description |
|---|
SkewHeap()
Constructs a new, empty heap, using the natural ordering of its keys.
|
SkewHeap(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 SkewHeap()
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.
public SkewHeap(Comparator<? super K> 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.
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)
insert in interface AddressableHeap<K,V>key - the element's keypublic AddressableHeap.Handle<K,V> insert(K key, V value)
insert in interface AddressableHeap<K,V>key - the element's keyvalue - the element's valuepublic 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)
MergeableAddressableHeapother 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.