it.unimi.dsi.util

Class TernaryIntervalSearchTree

java.lang.Object

it.unimi.dsi.fastutil.objects.AbstractObject2LongFunction<CharSequence>

it.unimi.dsi.util.AbstractPrefixMap

it.unimi.dsi.util.TernaryIntervalSearchTree

All Implemented Interfaces:

it.unimi.dsi.fastutil.Function<CharSequence,Long>, it.unimi.dsi.fastutil.objects.Object2LongFunction<CharSequence>, PrefixMap<MutableString>, StringMap<MutableString>, Serializable

public class TernaryIntervalSearchTree
extends AbstractPrefixMap
implements Serializable

Ternary interval search trees.

Ternary search trees are a data structure used to store words over an alphabet; they are a useful alternatives to tries when the alphabet is large.

Ternary interval search trees have the additional properties of being able to locate quickly intervals of words extending a given prefix (where “quickly” means that no more successful character comparisons than the prefix length are performed). They do so by storing at each node the number of words covered by that node.

This implementation exposes a number of interfaces: in particular, the set of words is seen as a lexicographically ordered ObjectList.

This class is mutable, but for the time it implements only add(CharSequence). Words cannot be removed.

See Also:

Serialized Form

Field Summary

Fields inherited from class it.unimi.dsi.util.AbstractPrefixMap

list, prefixMap, rangeMap

Fields inherited from class it.unimi.dsi.fastutil.objects.AbstractObject2LongFunction

defRetValue

Constructor Summary

Constructors

Constructor and Description
TernaryIntervalSearchTree() Creates a new empty ternary search tree.
TernaryIntervalSearchTree(Collection<? extends CharSequence> c) Creates a new empty ternary search tree and populates it with a given collection of character sequences.

Method Summary

Methods

Modifier and Type	Method and Description
boolean	add(CharSequence s)
boolean	containsKey(Object o)
Interval	getApproximatedInterval(CharSequence s)
protected long	getIndex(CharSequence s)
protected Interval	getInterval(CharSequence s) Returns the range of strings having a given prefix.
long	getLong(Object o)
protected MutableString	getTerm(int index, MutableString s) Writes a string specified by index into a MutableString.
static void	main(String[] arg)
int	size()

Methods inherited from class it.unimi.dsi.util.AbstractPrefixMap

list, prefixMap, rangeMap

Methods inherited from class it.unimi.dsi.fastutil.objects.AbstractObject2LongFunction

clear, defaultReturnValue, defaultReturnValue, get, put, put, remove, removeLong

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Methods inherited from interface it.unimi.dsi.fastutil.objects.Object2LongFunction

defaultReturnValue, defaultReturnValue, put, removeLong

Methods inherited from interface it.unimi.dsi.fastutil.Function

clear, get, put, remove

Constructor Detail

TernaryIntervalSearchTree

public TernaryIntervalSearchTree()

Creates a new empty ternary search tree.

TernaryIntervalSearchTree

public TernaryIntervalSearchTree(Collection<? extends CharSequence> c)

Creates a new empty ternary search tree and populates it with a given collection of character sequences.

Parameters:

c - a collection of character sequences.

Method Detail

getInterval

protected Interval getInterval(CharSequence s)

Description copied from class: AbstractPrefixMap

Returns the range of strings having a given prefix.

Specified by:

getInterval in class AbstractPrefixMap

Parameters:

s - a prefix.

Returns:

the corresponding range of strings as an interval.

getApproximatedInterval

public Interval getApproximatedInterval(CharSequence s)

getTerm

protected MutableString getTerm(int index,
                    MutableString s)

Description copied from class: AbstractPrefixMap

Writes a string specified by index into a MutableString.

Specified by:

getTerm in class AbstractPrefixMap

Parameters:

index - the index of a string.

s - a mutable string.

Returns:

string.

getIndex

protected long getIndex(CharSequence s)

containsKey

public boolean containsKey(Object o)

Specified by:

containsKey in interface it.unimi.dsi.fastutil.Function<CharSequence,Long>

getLong

public long getLong(Object o)

Specified by:

getLong in interface it.unimi.dsi.fastutil.objects.Object2LongFunction<CharSequence>

add

public boolean add(CharSequence s)

size

public int size()

Specified by:

size in interface it.unimi.dsi.fastutil.Function<CharSequence,Long>

main

public static void main(String[] arg)
                 throws IOException,
                        com.martiansoftware.jsap.JSAPException,
                        NoSuchMethodException

Throws:

IOException

com.martiansoftware.jsap.JSAPException

NoSuchMethodException