blogspot.software_and_algorithms.stern_library.data_structure

Class StaticIntervalTree<U extends Comparable<U>,T extends Interval<U>>

java.lang.Object

blogspot.software_and_algorithms.stern_library.data_structure.StaticIntervalTree<U,T>

public class StaticIntervalTree<U extends Comparable<U>,T extends Interval<U>>
extends Object

A static interval tree is a balanced binary search tree which is built to store a pre-specified set of intervals so that both point queries (queries that return intervals from the set which contain a query point) and overlapping interval queries (queries that return intervals from the set which overlap a query interval) can be completed in time O(log(n)+k), where n is the size of the pre-specified set of intervals and k is the size of the result set from the query.

While this implementation of a static interval tree is built to support a pre-specified set of intervals, intervals from this set may be added to and removed from the tree at will, giving a semi-static nature to the tree. The construction process completes in time O(n*log(n)) where n is the size of the set of intervals with which the tree is built.

Insertion and deletion of intervals to and from a constructed tree completes in time O(log(n)) where n is the size of the set of intervals with which the tree was built.

A constructed tree consumes linear space in the size of the set of intervals with which the tree was built.

Note that this implementation supports all three closed, open and half-open intervals.

Author:

Kevin L. Stern

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
protected static class	StaticIntervalTree.Node<U extends Comparable<U>,T extends Interval<U>> A node for a static interval tree is a binary tree node augmented with an associated point value and the ability to store intervals.

Constructor Summary

Constructors

Constructor and Description
StaticIntervalTree() Default constructor.

Method Summary

Modifier and Type	Method and Description
void	buildTree(Set<T> intervals) Build the interval tree to support the elements of the specified set of intervals.
void	clear() Clear the contents of the tree, leaving the tree structure intact.
boolean	delete(T interval) Delete the specified interval from this tree.
<V extends Collection<T>> V	fetchContainingIntervals(V target, U queryPoint) Fetch intervals containing the specified point.
<V extends Collection<T>> V	fetchOverlappingIntervals(V target, T queryInterval) Fetch intervals overlapping the specified interval.
int	getSize() Get the number of intervals being stored in the tree.
boolean	insert(T interval) Insert the specified interval into this tree.

Methods inherited from class java.lang.Object

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

Constructor Detail

StaticIntervalTree

public StaticIntervalTree()

Default constructor.

Method Detail

buildTree

public void buildTree(Set<T> intervals)

Build the interval tree to support the elements of the specified set of intervals. Note that this method does not insert intervals into the tree (this must be done via insert(Interval) after the tree is built).

Parameters:

intervals - the set of intervals for which the tree is to be built.

clear

public void clear()

Clear the contents of the tree, leaving the tree structure intact.

delete

public boolean delete(T interval)

Delete the specified interval from this tree.

Parameters:

interval - the interval to delete.

Returns:

true if an element was deleted as a result of this call, false otherwise.

fetchContainingIntervals

public <V extends Collection<T>> V fetchContainingIntervals(V target,
                                                            U queryPoint)

Fetch intervals containing the specified point.

Parameters:

target - the target Collection into which to place the desired intervals.

queryPoint - the query point.

Returns:

the target Collection.

fetchOverlappingIntervals

public <V extends Collection<T>> V fetchOverlappingIntervals(V target,
                                                             T queryInterval)

Fetch intervals overlapping the specified interval.

Parameters:

target - the target Collection into which to place the desired intervals.

queryInterval - the query interval.

Returns:

the target Collection.

getSize

public int getSize()

Get the number of intervals being stored in the tree.

Returns:

the number of intervals being stored in the tree.

insert

public boolean insert(T interval)

Insert the specified interval into this tree. Behavior is undefined when the interval was not included in the set of intervals presented at the most recent call to buildTree(Set).

Parameters:

interval - the interval to insert.

Returns:

true if an element was inserted as a result of this call, false otherwise.