Package io.openml.gearbox.disjointset

Enum Class DisjointSet.UnionAlgorithm

java.lang.Object

java.lang.Enum<DisjointSet.UnionAlgorithm>

io.openml.gearbox.disjointset.DisjointSet.UnionAlgorithm

All Implemented Interfaces:

Serializable, Comparable<DisjointSet.UnionAlgorithm>, Constable

Enclosing class:

DisjointSet<E>

public static enum DisjointSet.UnionAlgorithm
extends Enum<DisjointSet.UnionAlgorithm>

The algorithm used to merge two sets.

Nested Class Summary

Nested classes/interfaces inherited from class java.lang.Enum

Enum.EnumDesc<E extends Enum<E>>

Enum Constant Summary

Enum Constants

Enum Constant	Description
UNION_BY_RANK	Union by rank.
UNION_BY_SIZE	Union by size.

Method Summary

Modifier and Type	Method	Description
static DisjointSet.UnionAlgorithm	valueOf(String name)	Returns the enum constant of this class with the specified name.
static DisjointSet.UnionAlgorithm[]	values()	Returns an array containing the constants of this enum class, in the order they are declared.

Methods inherited from class java.lang.Enum

clone, compareTo, describeConstable, equals, finalize, getDeclaringClass, hashCode, name, ordinal, toString, valueOf

Methods inherited from class java.lang.Object

getClass, notify, notifyAll, wait, wait, wait

Enum Constant Details

UNION_BY_SIZE

public static final DisjointSet.UnionAlgorithm UNION_BY_SIZE

Union by size.

Two sets are merged based on the number of descendants (including the node itself). The set root with more descendants becomes the parent. If the two nodes have the same number of descendants, then the root of the first argument of DisjointSet.union(Object, Object) becomes the new parent. In both cases, the size of the new parent node is set to its new total number of descendants.

Union by size helps to keep the trees relatively balanced and prevents the formation of very tall, unbalanced trees.

UNION_BY_RANK

public static final DisjointSet.UnionAlgorithm UNION_BY_RANK

Union by rank.

Two sets are merged based on the rank, which is a zero-based upper bound for its height, of their respective roots. The set root with larger rank becomes the parent while the ranks for both do not change. If the ranks are the same, then the root of the first argument of DisjointSet.union(Object, Object) becomes the new parent and the rank of the first root is increased by 1.

Note that the "rank" is not the same as (node) height. Ranks does not accurately reflect the height. For this reason, rank is never updated after path-compression.

Union by rank helps maintain flat trees, which improves the efficiency of Find operations.

Method Details

values

public static DisjointSet.UnionAlgorithm[] values()

Returns an array containing the constants of this enum class, in the order they are declared.

Returns:

an array containing the constants of this enum class, in the order they are declared

valueOf

public static DisjointSet.UnionAlgorithm valueOf(String name)

Returns the enum constant of this class with the specified name. The string must match exactly an identifier used to declare an enum constant in this class. (Extraneous whitespace characters are not permitted.)

Parameters:

name - the name of the enum constant to be returned.

Returns:

the enum constant with the specified name

Throws:

IllegalArgumentException - if this enum class has no constant with the specified name

NullPointerException - if the argument is null