Class IntOpenHashSet
- All Implemented Interfaces:
Hash
,IntCollection
,IntIterable
,IntSet
,Serializable
,Cloneable
,Iterable<Integer>
,Collection<Integer>
,Set<Integer>
public class IntOpenHashSet extends AbstractIntSet implements Serializable, Cloneable, Hash
Instances of this class use a hash table to represent a set. The table is filled up to a specified load factor, and then doubled in size to accommodate new entries. If the table is emptied below one fourth of the load factor, it is halved in size; however, the table is never reduced to a size smaller than that at creation time: this approach makes it possible to create sets with a large capacity in which insertions and deletions do not cause immediately rehashing. Moreover, halving is not performed when deleting entries from an iterator, as it would interfere with the iteration process.
Note that clear()
does not modify the hash table size. Rather, a
family of trimming methods lets you control the size of
the table; this is particularly useful if you reuse instances of this class.
- See Also:
Hash
,HashCommon
, Serialized Form
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Nested Class Summary
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Field Summary
Fields inherited from interface it.unimi.dsi.fastutil.Hash
DEFAULT_GROWTH_FACTOR, DEFAULT_INITIAL_SIZE, DEFAULT_LOAD_FACTOR, FAST_LOAD_FACTOR, FREE, OCCUPIED, PRIMES, REMOVED, VERY_FAST_LOAD_FACTOR
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Constructor Summary
Constructors Constructor Description IntOpenHashSet()
Creates a new hash set with initial expectedHash.DEFAULT_INITIAL_SIZE
elements andHash.DEFAULT_LOAD_FACTOR
as load factor.IntOpenHashSet(int expected)
Creates a new hash set withHash.DEFAULT_LOAD_FACTOR
as load factor.IntOpenHashSet(int[] a)
Creates a new hash set withHash.DEFAULT_LOAD_FACTOR
as load factor copying the elements of an array.IntOpenHashSet(int[] a, float f)
Creates a new hash set copying the elements of an array.IntOpenHashSet(int[] a, int offset, int length)
Creates a new hash set withHash.DEFAULT_LOAD_FACTOR
as load factor and fills it with the elements of a given array.IntOpenHashSet(int[] a, int offset, int length, float f)
Creates a new hash set and fills it with the elements of a given array.IntOpenHashSet(int expected, float f)
Creates a new hash set.IntOpenHashSet(IntCollection c)
Creates a new hash set withHash.DEFAULT_LOAD_FACTOR
as load factor copying a given type-specific collection.IntOpenHashSet(IntCollection c, float f)
Creates a new hash set copying a given type-specific collection.IntOpenHashSet(IntIterator i)
Creates a new hash set withHash.DEFAULT_LOAD_FACTOR
as load factor using elements provided by a type-specific iterator.IntOpenHashSet(IntIterator i, float f)
Creates a new hash set using elements provided by a type-specific iterator.IntOpenHashSet(Collection<? extends Integer> c)
Creates a new hash set withHash.DEFAULT_LOAD_FACTOR
as load factor copying a given collection.IntOpenHashSet(Collection<? extends Integer> c, float f)
Creates a new hash set copying a given collection.IntOpenHashSet(Iterator<?> i)
Creates a new hash set withHash.DEFAULT_LOAD_FACTOR
as load factor using elements provided by an iterator.IntOpenHashSet(Iterator<?> i, float f)
Creates a new hash set using elements provided by an iterator. -
Method Summary
Modifier and Type Method Description boolean
add(int k)
Ensures that this collection contains the specified element (optional operation).boolean
addAll(IntCollection c)
Adds all elements of the given type-specific collection to this collection.boolean
addAll(Collection<? extends Integer> c)
void
clear()
IntOpenHashSet
clone()
Returns a deep copy of this set.boolean
contains(int k)
Returnstrue
if this collection contains the specified element.int
hashCode()
Returns a hash code for this set.boolean
isEmpty()
IntIterator
iterator()
Returns a type-specific iterator on the elements of this collection.boolean
remove(int k)
Removes an element from this set.int
size()
boolean
trim()
Rehashes this set, making the table as small as possible.boolean
trim(int n)
Rehashes this set if the table is too large.Methods inherited from class it.unimi.dsi.fastutil.ints.AbstractIntCollection
add, contains, containsAll, remove, removeAll, retainAll, toArray, toIntArray, toIntArray, toString
Methods inherited from class java.util.AbstractCollection
containsAll, removeAll, retainAll, toArray, toArray
Methods inherited from interface it.unimi.dsi.fastutil.ints.IntCollection
containsAll, removeAll, removeIf, removeIf, retainAll, toArray, toIntArray, toIntArray
Methods inherited from interface java.util.Set
containsAll, removeAll, retainAll, spliterator, toArray, toArray
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Constructor Details
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IntOpenHashSet
public IntOpenHashSet(int expected, float f)Creates a new hash set.The actual table size will be the least power of two greater than
expected
/f
.- Parameters:
expected
- the expected number of elements in the hash set.f
- the load factor.
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IntOpenHashSet
public IntOpenHashSet(int expected)Creates a new hash set withHash.DEFAULT_LOAD_FACTOR
as load factor.- Parameters:
expected
- the expected number of elements in the hash set.
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IntOpenHashSet
public IntOpenHashSet()Creates a new hash set with initial expectedHash.DEFAULT_INITIAL_SIZE
elements andHash.DEFAULT_LOAD_FACTOR
as load factor. -
IntOpenHashSet
Creates a new hash set copying a given collection.- Parameters:
c
- aCollection
to be copied into the new hash set.f
- the load factor.
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IntOpenHashSet
Creates a new hash set withHash.DEFAULT_LOAD_FACTOR
as load factor copying a given collection.- Parameters:
c
- aCollection
to be copied into the new hash set.
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IntOpenHashSet
Creates a new hash set copying a given type-specific collection.- Parameters:
c
- a type-specific collection to be copied into the new hash set.f
- the load factor.
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IntOpenHashSet
Creates a new hash set withHash.DEFAULT_LOAD_FACTOR
as load factor copying a given type-specific collection.- Parameters:
c
- a type-specific collection to be copied into the new hash set.
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IntOpenHashSet
Creates a new hash set using elements provided by a type-specific iterator.- Parameters:
i
- a type-specific iterator whose elements will fill the set.f
- the load factor.
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IntOpenHashSet
Creates a new hash set withHash.DEFAULT_LOAD_FACTOR
as load factor using elements provided by a type-specific iterator.- Parameters:
i
- a type-specific iterator whose elements will fill the set.
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IntOpenHashSet
Creates a new hash set using elements provided by an iterator.- Parameters:
i
- an iterator whose elements will fill the set.f
- the load factor.
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IntOpenHashSet
Creates a new hash set withHash.DEFAULT_LOAD_FACTOR
as load factor using elements provided by an iterator.- Parameters:
i
- an iterator whose elements will fill the set.
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IntOpenHashSet
public IntOpenHashSet(int[] a, int offset, int length, float f)Creates a new hash set and fills it with the elements of a given array.- Parameters:
a
- an array whose elements will be used to fill the set.offset
- the first element to use.length
- the number of elements to use.f
- the load factor.
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IntOpenHashSet
public IntOpenHashSet(int[] a, int offset, int length)Creates a new hash set withHash.DEFAULT_LOAD_FACTOR
as load factor and fills it with the elements of a given array.- Parameters:
a
- an array whose elements will be used to fill the set.offset
- the first element to use.length
- the number of elements to use.
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IntOpenHashSet
public IntOpenHashSet(int[] a, float f)Creates a new hash set copying the elements of an array.- Parameters:
a
- an array to be copied into the new hash set.f
- the load factor.
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IntOpenHashSet
public IntOpenHashSet(int[] a)Creates a new hash set withHash.DEFAULT_LOAD_FACTOR
as load factor copying the elements of an array.- Parameters:
a
- an array to be copied into the new hash set.
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Method Details
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addAll
Description copied from interface:IntCollection
Adds all elements of the given type-specific collection to this collection.- Specified by:
addAll
in interfaceIntCollection
- Overrides:
addAll
in classAbstractIntCollection
- Parameters:
c
- a type-specific collection.- Returns:
true
if this collection changed as a result of the call.- See Also:
Collection.addAll(Collection)
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addAll
- Specified by:
addAll
in interfaceCollection<Integer>
- Specified by:
addAll
in interfaceSet<Integer>
- Overrides:
addAll
in classAbstractCollection<Integer>
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add
public boolean add(int k)Description copied from class:AbstractIntCollection
Ensures that this collection contains the specified element (optional operation).This implementation always throws an
UnsupportedOperationException
.- Specified by:
add
in interfaceIntCollection
- Overrides:
add
in classAbstractIntCollection
- See Also:
Collection.add(Object)
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remove
public boolean remove(int k)Description copied from class:AbstractIntSet
Removes an element from this set.Note that the corresponding method of a type-specific collection is
rem()
. This unfortunate situation is caused by the clash with the similarly named index-based method in theList
interface. Delegates to the type-specificrem()
method implemented by type-specific abstractCollection
superclass.- Specified by:
remove
in interfaceIntSet
- Overrides:
remove
in classAbstractIntSet
- See Also:
Collection.remove(Object)
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contains
public boolean contains(int k)Description copied from class:AbstractIntCollection
Returnstrue
if this collection contains the specified element.This implementation iterates over the elements in the collection, looking for the specified element.
- Specified by:
contains
in interfaceIntCollection
- Overrides:
contains
in classAbstractIntCollection
- See Also:
Collection.contains(Object)
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clear
public void clear()- Specified by:
clear
in interfaceCollection<Integer>
- Specified by:
clear
in interfaceSet<Integer>
- Overrides:
clear
in classAbstractCollection<Integer>
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size
public int size()- Specified by:
size
in interfaceCollection<Integer>
- Specified by:
size
in interfaceSet<Integer>
- Specified by:
size
in classAbstractCollection<Integer>
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isEmpty
public boolean isEmpty()- Specified by:
isEmpty
in interfaceCollection<Integer>
- Specified by:
isEmpty
in interfaceSet<Integer>
- Overrides:
isEmpty
in classAbstractCollection<Integer>
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iterator
Description copied from interface:IntCollection
Returns a type-specific iterator on the elements of this collection.Note that this specification strengthens the one given in
Iterable.iterator()
, which was already strengthened in the corresponding type-specific class, but was weakened by the fact that this interface extendsCollection
.- Specified by:
iterator
in interfaceCollection<Integer>
- Specified by:
iterator
in interfaceIntCollection
- Specified by:
iterator
in interfaceIntIterable
- Specified by:
iterator
in interfaceIntSet
- Specified by:
iterator
in interfaceIterable<Integer>
- Specified by:
iterator
in interfaceSet<Integer>
- Specified by:
iterator
in classAbstractIntSet
- Returns:
- a type-specific iterator on the elements of this collection.
- See Also:
Iterable.iterator()
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trim
public boolean trim()Rehashes this set, making the table as small as possible.This method rehashes the table to the smallest size satisfying the load factor. It can be used when the set will not be changed anymore, so to optimize access speed and size.
If the table size is already the minimum possible, this method does nothing.
- Returns:
- true if there was enough memory to trim the set.
- See Also:
trim(int)
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trim
public boolean trim(int n)Rehashes this set if the table is too large.Let N be the smallest table size that can hold
max(n,
entries, still satisfying the load factor. If the current table size is smaller than or equal to N, this method does nothing. Otherwise, it rehashes this set in a table of size N.size()
)This method is useful when reusing sets. Clearing a set leaves the table size untouched. If you are reusing a set many times, you can call this method with a typical size to avoid keeping around a very large table just because of a few large transient sets.
- Parameters:
n
- the threshold for the trimming.- Returns:
- true if there was enough memory to trim the set.
- See Also:
trim()
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clone
Returns a deep copy of this set.This method performs a deep copy of this hash set; the data stored in the set, however, is not cloned. Note that this makes a difference only for object keys.
- Returns:
- a deep copy of this set.
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hashCode
public int hashCode()Returns a hash code for this set. This method overrides the generic method provided by the superclass. Sinceequals()
is not overriden, it is important that the value returned by this method is the same value as the one returned by the overriden method.- Specified by:
hashCode
in interfaceCollection<Integer>
- Specified by:
hashCode
in interfaceSet<Integer>
- Overrides:
hashCode
in classAbstractIntSet
- Returns:
- a hash code for this set.
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