net.automatalib.commons.util

Class UnionFind

java.lang.Object

net.automatalib.commons.util.UnionFind

public final class UnionFind
extends Object

The well-known disjoint-set forest data structure for dealing with partitions on a fixed-range integer domain.

Author:

fhowar, Malte Isberner

Constructor Summary

Constructors

Constructor and Description
UnionFind(int n) Initializes the disjoint-set data structure.

Method Summary

Modifier and Type	Method and Description
int	find(int x) Finds the set of a given element, and compresses the path to the root node.
int	link(int x, int y) Unites two given sets.
int	size()
int	union(int p, int q) Unites the sets containing the two given elements.

Methods inherited from class java.lang.Object

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

Constructor Detail

UnionFind

public UnionFind(int n)

Initializes the disjoint-set data structure.

Parameters:

n - the overall size of the domain

Method Detail

size

public int size()

union

public int union(int p,
                 int q)

Unites the sets containing the two given elements.

Parameters:

p - the first element

q - the second element

Returns:

the identifier of the resulting set

link

public int link(int x,
                int y)

Unites two given sets. Note that the behavior of this method is not specified if the given parameters are normal elements and no set identifiers.

Parameters:

x - the first set

y - the second set

Returns:

the identifier of the resulting set (either x or y)

find

public int find(int x)

Finds the set of a given element, and compresses the path to the root node.

Parameters:

x - the element

Returns:

the identifier of the set which contains the given element