UnionFind (Compiler)

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com.google.javascript.jscomp.graph
Interface UnionFind<E>


Type Parameters:: E - element type

All Known Implementing Classes:: StandardUnionFind

public interface UnionFind<E>

Union-Find is a classical algorithm used to find connected components in graph theory.

Each equivalence class has a representative element that is chosen arbitrarily and is used to determine if two elements are members of the same class.

See algorithmist for more detail.

Method Summary
`void`	`add(E e)` Adds the given element to a new set if it is not already in a set.
`Collection<Set<E>>`	`allEquivalenceClasses()` Returns an immutable collection containing all equivalence classes.
`boolean`	`areEquivalent(E a, E b)` Returns true if `a` and `b` belong to the same equivalence class.
`Set<E>`	`elements()` Returns an unmodifiable set of all elements added to the UnionFind.
`E`	`find(E e)` Returns the representative of the equivalence class of `e`.
`Set<E>`	`findAll(E value)` Returns the elements in the same equivalence class as `value`.
`E`	`union(E a, E b)` Unions the equivalence classes of `a` and `b` and returns the representative of the resulting equivalence class.

Method Detail

add

void add(E e)

Adds the given element to a new set if it is not already in a set.

Throws:: UnsupportedOperationException - if the add operation is not supported by this union-find.

union

E union(E a,
        E b)

Unions the equivalence classes of a and b and returns the representative of the resulting equivalence class. The elements will be added if they are not already present.

Throws:: UnsupportedOperationException - if the add operation is not supported by this union-find.

find

E find(E e)

Returns the representative of the equivalence class of e.

areEquivalent

boolean areEquivalent(E a,
                      E b)

Returns true if a and b belong to the same equivalence class.

Throws:: IllegalArgumentException - if any argument is not an element of this structure.

elements

Set<E> elements()

Returns an unmodifiable set of all elements added to the UnionFind.

allEquivalenceClasses

Collection<Set<E>> allEquivalenceClasses()

Returns an immutable collection containing all equivalence classes. The returned collection represents a snapshot of the current state and will not reflect changes made to the data structure.

findAll

Set<E> findAll(E value)

Returns the elements in the same equivalence class as value.

Returns:: an unmodifiable view. As equivalence classes are merged, this set will reflect those changes.
Throws:: IllegalArgumentException - if a requested element does not belong to the structure.