Class BinaryArrayAddressableHeap<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 implementation uses an array in order to store the elements and
automatically maintains the size of the array much like a
Vector
does, providing amortized O(log(n)) time cost for
the insert
and deleteMin
operations. Operation
findMin
, is a worst-case O(1) operation. Operations delete
and decreaseKey
take worst-case O(log(n)) time. The bounds are
worst-case if the user initializes the heap with a capacity larger or equal
to the total number of elements that are going to be inserted into the heap.
Constructing such a heap from an array of elements can be performed using the
method heapify(Object[], Object[])
or
heapify(Object[], Object[], Comparator)
in linear time.
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 classes/interfaces inherited from class org.jheaps.array.AbstractArrayAddressableHeap
AbstractArrayAddressableHeap.ArrayHandle
Nested classes/interfaces inherited from interface org.jheaps.AddressableHeap
AddressableHeap.Handle<K,
V> -
Field Summary
FieldsModifier and TypeFieldDescriptionstatic final int
Default initial capacity of the binary heap.private static final long
Fields inherited from class org.jheaps.array.AbstractArrayAddressableHeap
array, comparator, DOWNSIZING_MIN_HEAP_CAPACITY, MAX_HEAP_CAPACITY, MIN_HEAP_CAPACITY, minCapacity, NO_INDEX, size
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Constructor Summary
ConstructorsConstructorDescriptionConstructs a new, empty heap, using the natural ordering of its keys.BinaryArrayAddressableHeap
(int capacity) Constructs a new, empty heap, with a provided initial capacity using the natural ordering of its keys.BinaryArrayAddressableHeap
(Comparator<? super K> comparator) Constructs a new, empty heap, ordered according to the given comparator.BinaryArrayAddressableHeap
(Comparator<? super K> comparator, int capacity) Constructs a new, empty heap, with a provided initial capacity ordered according to the given comparator. -
Method Summary
Modifier and TypeMethodDescriptionprotected void
ensureCapacity
(int capacity) Ensure that the array representation has the necessary capacity.protected void
fixdown
(int k) protected void
fixdownWithComparator
(int k) protected void
fixup
(int k) protected void
fixupWithComparator
(int k) protected void
forceFixup
(int k) Get an iterator for all handles currently in the heap.static <K,
V> BinaryArrayAddressableHeap<K, V> heapify
(K[] keys, V[] values) Create a heap from an array of elements.static <K,
V> BinaryArrayAddressableHeap<K, V> heapify
(K[] keys, V[] values, Comparator<? super K> comparator) Create a heap from an array of elements.Methods inherited from class org.jheaps.array.AbstractArrayAddressableHeap
checkCapacity, clear, comparator, deleteMin, findMin, insert, insert, isEmpty, size
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Field Details
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serialVersionUID
private static final long serialVersionUID- See Also:
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DEFAULT_HEAP_CAPACITY
public static final int DEFAULT_HEAP_CAPACITYDefault initial capacity of the binary heap.- See Also:
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Constructor Details
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BinaryArrayAddressableHeap
public BinaryArrayAddressableHeap()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
.The initial capacity of the heap is
DEFAULT_HEAP_CAPACITY
and adjusts automatically based on the sequence of insertions and deletions. -
BinaryArrayAddressableHeap
public BinaryArrayAddressableHeap(int capacity) Constructs a new, empty heap, with a provided initial capacity 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
.The initial capacity of the heap is provided by the user and is adjusted automatically based on the sequence of insertions and deletions. The capacity will never become smaller than the initial requested capacity.
- Parameters:
capacity
- the initial heap capacity
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BinaryArrayAddressableHeap
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
.The initial capacity of the heap is
DEFAULT_HEAP_CAPACITY
and adjusts automatically based on the sequence of insertions and deletions.- Parameters:
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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BinaryArrayAddressableHeap
Constructs a new, empty heap, with a provided initial capacity 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
.The initial capacity of the heap is provided by the user and is adjusted automatically based on the sequence of insertions and deletions. The capacity will never become smaller than the initial requested capacity.
- Parameters:
comparator
- the comparator that will be used to order this heap. Ifnull
, the natural ordering of the keys will be used.capacity
- the initial heap capacity
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Method Details
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heapify
Create a heap from an array of elements. The elements of the array are not destroyed. The method has linear time complexity.- Type Parameters:
K
- the type of keys maintained by the heapV
- the type of values maintained by the heap- Parameters:
keys
- an array of keysvalues
- an array of values- Returns:
- a binary heap
- Throws:
IllegalArgumentException
- in case the array is null
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heapify
public static <K,V> BinaryArrayAddressableHeap<K,V> heapify(K[] keys, V[] values, Comparator<? super K> comparator) Create a heap from an array of elements. The elements of the array are not destroyed. The method has linear time complexity.- Type Parameters:
K
- the type of keys maintained by the heapV
- the type of values maintained by the heap- Parameters:
keys
- an array of keysvalues
- an array of valuescomparator
- the comparator to use- Returns:
- a binary heap
- Throws:
IllegalArgumentException
- in case the array is null
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handlesIterator
Get an iterator for all handles currently in the heap. This method is especially useful when building a heap using the heapify method. Unspecified behavior will occur if the heap is modified while using this iterator.- Returns:
- an iterator which will return all handles of the heap
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ensureCapacity
protected void ensureCapacity(int capacity) Ensure that the array representation has the necessary capacity.- Specified by:
ensureCapacity
in classAbstractArrayAddressableHeap<K,
V> - Parameters:
capacity
- the requested capacity
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forceFixup
protected void forceFixup(int k) - Specified by:
forceFixup
in classAbstractArrayAddressableHeap<K,
V>
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fixup
protected void fixup(int k) - Specified by:
fixup
in classAbstractArrayAddressableHeap<K,
V>
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fixupWithComparator
protected void fixupWithComparator(int k) - Specified by:
fixupWithComparator
in classAbstractArrayAddressableHeap<K,
V>
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fixdown
protected void fixdown(int k) - Specified by:
fixdown
in classAbstractArrayAddressableHeap<K,
V>
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fixdownWithComparator
protected void fixdownWithComparator(int k) - Specified by:
fixdownWithComparator
in classAbstractArrayAddressableHeap<K,
V>
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