Class DaryTreeAddressableHeap<K,V>
- java.lang.Object
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- org.jheaps.tree.DaryTreeAddressableHeap<K,V>
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- Type Parameters:
K
- the type of keys maintained by this heapV
- the type of values maintained by this heap
- All Implemented Interfaces:
java.io.Serializable
,AddressableHeap<K,V>
public class DaryTreeAddressableHeap<K,V> extends java.lang.Object implements AddressableHeap<K,V>, java.io.Serializable
An explicit d-ary tree addressable heap. The heap is sorted according to the natural ordering of its keys, or by aComparator
provided at heap creation time, depending on which constructor is used.The worst-case cost of
insert
,deleteMin
,delete
anddecreaceKey
operations is O(d log_d(n)) and the cost offindMin
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 theHeap
interface. (SeeComparable
orComparator
for a precise definition of consistent with equals.) This is so because theHeap
interface is defined in terms of theequals
operation, but a binary heap performs all key comparisons using itscompareTo
(orcompare
) 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 withequals
; it just fails to obey the general contract of theHeap
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:
AddressableHeap
,Comparable
,Comparator
, Serialized Form
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Nested Class Summary
Nested Classes Modifier and Type Class Description private class
DaryTreeAddressableHeap.Node
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Nested classes/interfaces inherited from interface org.jheaps.AddressableHeap
AddressableHeap.Handle<K,V>
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Field Summary
Fields Modifier and Type Field Description private DaryTreeAddressableHeap.Node[]
aux
Auxiliary for swapping children.private java.util.Comparator<? super K>
comparator
The comparator used to maintain order in this heap, or null if it uses the natural ordering of its keys.private int
d
Branching factor.private int
log2d
Base 2 logarithm of branching factor.private DaryTreeAddressableHeap.Node
root
Root node of the heapprivate static long
serialVersionUID
private long
size
Size of the heap
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Constructor Summary
Constructors Constructor Description DaryTreeAddressableHeap(int d)
Constructs a new, empty heap, using the natural ordering of its keys.DaryTreeAddressableHeap(int d, java.util.Comparator<? super K> comparator)
Constructs a new, empty heap, ordered according to the given comparator.
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Method Summary
All Methods Instance Methods Concrete Methods Modifier and Type Method Description void
clear()
Clear all the elements of the heap.java.util.Comparator<? super K>
comparator()
Returns the comparator used to order the keys in this AddressableHeap, ornull
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.private DaryTreeAddressableHeap.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
fixdown(DaryTreeAddressableHeap.Node n)
private void
fixup(DaryTreeAddressableHeap.Node n)
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()
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.Node a, DaryTreeAddressableHeap.Node b)
Swap two nodes
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Field Detail
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serialVersionUID
private static final long serialVersionUID
- See Also:
- Constant Field Values
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comparator
private final java.util.Comparator<? super K> comparator
The comparator used to maintain order in this heap, or null if it uses the natural ordering of its keys.
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size
private long size
Size of the heap
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root
private DaryTreeAddressableHeap.Node root
Root node of the heap
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d
private final int d
Branching factor. Always a power of two.
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log2d
private final int log2d
Base 2 logarithm of branching factor.
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aux
private DaryTreeAddressableHeap.Node[] aux
Auxiliary for swapping children.
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Constructor Detail
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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.
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DaryTreeAddressableHeap
public DaryTreeAddressableHeap(int d, java.util.Comparator<? super K> comparator)
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 Detail
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insert
public AddressableHeap.Handle<K,V> insert(K key, V value)
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
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insert
public AddressableHeap.Handle<K,V> insert(K key)
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
public AddressableHeap.Handle<K,V> 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
public AddressableHeap.Handle<K,V> 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
public java.util.Comparator<? super K> 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
private DaryTreeAddressableHeap.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. 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
private void fixup(DaryTreeAddressableHeap.Node n)
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fixdown
private void fixdown(DaryTreeAddressableHeap.Node n)
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swap
private void swap(DaryTreeAddressableHeap.Node a, DaryTreeAddressableHeap.Node b)
Swap two nodes- Parameters:
a
- first nodeb
- second node
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