Class DaryTreeAddressableHeap<K,V>
- Type Parameters:
K
- the type of keys maintained by this heapV
- the type of values maintained by this heap
- All Implemented Interfaces:
Serializable
,AddressableHeap<K,
V>
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:
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Nested Class Summary
Nested ClassesNested classes/interfaces inherited from interface org.jheaps.AddressableHeap
AddressableHeap.Handle<K,
V> -
Field Summary
FieldsModifier and TypeFieldDescriptionprivate DaryTreeAddressableHeap<K,
V>.Node[] Auxiliary for swapping children.private final Comparator
<? super K> The comparator used to maintain order in this heap, or null if it uses the natural ordering of its keys.private final int
Branching factor.private final int
Base 2 logarithm of branching factor.private DaryTreeAddressableHeap<K,
V>.Node Root node of the heapprivate static final long
private long
Size of the heap -
Constructor Summary
ConstructorsConstructorDescriptionDaryTreeAddressableHeap
(int d) Constructs a new, empty heap, using the natural ordering of its keys.DaryTreeAddressableHeap
(int d, Comparator<? super K> comparator) Constructs a new, empty heap, ordered according to the given comparator. -
Method Summary
Modifier and TypeMethodDescriptionvoid
clear()
Clear all the elements of the heap.Comparator
<? super K> Returns the comparator used to order the keys in this AddressableHeap, ornull
if this heap uses the natural ordering of its keys.Delete and return an element with the minimum key.findMin()
Find an element with the minimum key.private DaryTreeAddressableHeap<K,
V>.Node findNode
(long node) Start at the root and traverse the tree in order to find a particular node based on its numbering on a level-order traversal of the tree.private void
private void
Insert a new element into the heap with a null value.Insert a new element into the heap.boolean
isEmpty()
Returnstrue
if this heap is empty.private int
log2
(long n) Calculate the floor of the binary logarithm of n.long
size()
Returns the number of elements in the heap.private void
swap
(DaryTreeAddressableHeap<K, V>.Node a, DaryTreeAddressableHeap<K, V>.Node b) Swap two nodes
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Field Details
-
serialVersionUID
private static final long serialVersionUID- See Also:
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comparator
The comparator used to maintain order in this heap, or null if it uses the natural ordering of its keys. -
size
private long sizeSize of the heap -
root
Root node of the heap -
d
private final int dBranching factor. Always a power of two. -
log2d
private final int log2dBase 2 logarithm of branching factor. -
aux
Auxiliary for swapping children.
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Constructor Details
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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 aClassCastException
for any keysk1
andk2
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), theinsert(Object key)
call will throw aClassCastException
.- Parameters:
d
- the branching factor. Should be a power of 2.
-
DaryTreeAddressableHeap
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 aClassCastException
for any keysk1
andk2
in the heap. If the user attempts to put a key into the heap that violates this constraint, theinsert(Object key)
call will throw aClassCastException
.- Parameters:
d
- the branching factor. Should be a power of 2.comparator
- the comparator that will be used to order this heap. Ifnull
, the natural ordering of the keys will be used.
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Method Details
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insert
Description copied from interface:AddressableHeap
Insert a new element into the heap.- Specified by:
insert
in interfaceAddressableHeap<K,
V> - Parameters:
key
- the element's keyvalue
- the element's value- Returns:
- a handle for the newly added element
-
insert
Description copied from interface:AddressableHeap
Insert a new element into the heap with a null value.- Specified by:
insert
in interfaceAddressableHeap<K,
V> - Parameters:
key
- the element's key- Returns:
- a handle for the newly added element
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findMin
Description copied from interface:AddressableHeap
Find an element with the minimum key.- Specified by:
findMin
in interfaceAddressableHeap<K,
V> - Returns:
- a handle to an element with minimum key
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deleteMin
Description copied from interface:AddressableHeap
Delete and return an element with the minimum key. If multiple such elements exists, only one of them will be deleted. After the element is deleted the handle is invalidated and only methodAddressableHeap.Handle.getKey()
andAddressableHeap.Handle.getValue()
can be used.- Specified by:
deleteMin
in interfaceAddressableHeap<K,
V> - Returns:
- a handle to the deleted element with minimum key
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isEmpty
public boolean isEmpty()Description copied from interface:AddressableHeap
Returnstrue
if this heap is empty.- Specified by:
isEmpty
in interfaceAddressableHeap<K,
V> - Returns:
true
if this heap is empty,false
otherwise
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size
public long size()Description copied from interface:AddressableHeap
Returns the number of elements in the heap.- Specified by:
size
in interfaceAddressableHeap<K,
V> - Returns:
- the number of elements in the heap
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clear
public void clear()Description copied from interface:AddressableHeap
Clear all the elements of the heap. After calling this method all handles should be considered invalidated and the behavior of methodsAddressableHeap.Handle.decreaseKey(Object)
andAddressableHeap.Handle.delete()
is undefined.- Specified by:
clear
in interfaceAddressableHeap<K,
V>
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comparator
Description copied from interface:AddressableHeap
Returns the comparator used to order the keys in this AddressableHeap, ornull
if this heap uses the natural ordering of its keys.- Specified by:
comparator
in interfaceAddressableHeap<K,
V> - Returns:
- the comparator used to order the keys in this heap, or
null
if this addressable heap uses the natural ordering of its keys
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findNode
Start at the root and traverse the tree in order to find a particular node based on its numbering on a level-order traversal of the tree. Uses the bit representation to keep the cost log_d(n).- Parameters:
node
- the node number assuming that the root node is number zero
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log2
private int log2(long n) Calculate the floor of the binary logarithm of n.- Parameters:
n
- the input number- Returns:
- the binary logarithm
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fixup
-
fixdown
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swap
Swap two nodes- Parameters:
a
- first nodeb
- second node
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