Method permutations

output/java_guava/1.4.16/Collections2.java:562–565

Returns a Collection of all the permutations of the specified Collection. Notes: This is an implementation of the Plain Changes algorithm for permutations generation, described in Knuth's "The Art of Computer Programming", Volume 4, Chapter 7, Section 7.2.1.2. If the i

(Collection<E> elements)

   */

  @Beta
  public static <E> Collection<List<E>> permutations(Collection<E> elements) {
    return new PermutationCollection<E>(ImmutableList.copyOf(elements));
  }

  private static final class PermutationCollection<E> extends AbstractCollection<List<E>> {
    final ImmutableList<E> inputList;