assertEquals(multimap, copy);
  }

  private static final Comparator<Double> KEY_COMPARATOR = Ordering.natural();

  private static final Comparator<Double> VALUE_COMPARATOR =
      Ordering.<Double>natural().reverse().nullsFirst();

  /**
   * Test that creating one TreeMultimap from another does not copy the comparators from the source
   * TreeMultimap.
   */
  public void testCreateFromTreeMultimap() {

          Comparator<? super E> comparator,
          @ParametricNullness E key,
          List<? extends E> list,
          int foundIndex) {
        return FIRST_PRESENT.resultIndex(comparator, key, list, foundIndex) - 1;
      }
    };

    abstract <E extends @Nullable Object> int resultIndex(
        Comparator<? super E> comparator,
        @ParametricNullness E key,

            new byte[] {GREATEST, GREATEST, GREATEST});

    Comparator<byte[]> comparator = SignedBytes.lexicographicalComparator();
    Helpers.testComparator(comparator, ordered);
  }

  @J2ktIncompatible
  @GwtIncompatible // SerializableTester
  public void testLexicographicalComparatorSerializable() {
    Comparator<byte[]> comparator = SignedBytes.lexicographicalComparator();

    ImmutableSortedMap<String, Integer> copy = ImmutableSortedMap.copyOf(original, comparator);
    assertMapEquals(copy, "two", 2, "three", 3, "one", 1);
    assertSame(copy, ImmutableSortedMap.copyOf(copy, comparator));
    assertSame(comparator, copy.comparator());
  }

  public void testCopyOfImmutableSortedSetDifferentComparator() {
    Comparator<String> comparator = Ordering.<String>natural().reverse();

   * bufferSize ≥ k, then we can ignore any elements greater than this value.
   */
  @CheckForNull private T threshold;

  @SuppressWarnings("unchecked") // TODO(cpovirk): Consider storing Object[] instead of T[].
  private TopKSelector(Comparator<? super T> comparator, int k) {
    this.comparator = checkNotNull(comparator, "comparator");
    this.k = k;
    checkArgument(k >= 0, "k (%s) must be >= 0", k);

  abstract SortedMultiset<E> forwardMultiset();

  @Nullable private transient Comparator<? super E> comparator;

  @Override
  public Comparator<? super E> comparator() {
    Comparator<? super E> result = comparator;
    if (result == null) {
      return comparator = Ordering.from(forwardMultiset().comparator()).<E>reverse();
    }
    return result;
  }

    @Override
    protected List<String> create(String[] elements) {
      Comparator<String> comparator = createExplicitComparator(elements);
      ImmutableSet<String> set = ImmutableSortedSet.copyOf(comparator, Arrays.asList(elements));
      return set.asList();
    }
  }

      Iterable<E> elements, Comparator<? super E> comparator) {
    return new OrderedPermutationCollection<E>(elements, comparator);
  }

  private static final class OrderedPermutationCollection<E> extends AbstractCollection<List<E>> {
    final ImmutableList<E> inputList;
    final Comparator<? super E> comparator;
    final int size;

    OrderedPermutationCollection(Iterable<E> input, Comparator<? super E> comparator) {

  }

  /** Create and populate a {@code TreeMultimap} with explicit comparators. */
  private TreeMultimap<@Nullable String, @Nullable Integer> createPopulate() {
    TreeMultimap<@Nullable String, @Nullable Integer> multimap =
        TreeMultimap.create(StringLength.COMPARATOR, DECREASING_INT_COMPARATOR);
    multimap.put("google", 2);
    multimap.put("google", 6);

    assertEquals(multimap, copy);
  }

  private static final Comparator<Double> KEY_COMPARATOR = Ordering.natural();

  private static final Comparator<Double> VALUE_COMPARATOR =
      Ordering.<Double>natural().reverse().nullsFirst();

  /**
   * Test that creating one TreeMultimap from another does not copy the comparators from the source
   * TreeMultimap.
   */
  public void testCreateFromTreeMultimap() {