import java.util.Arrays;
import java.util.Collection;
import java.util.Comparator;
import java.util.Map;
import java.util.function.BinaryOperator;
import java.util.function.Function;
import java.util.stream.Collector;
import java.util.stream.Collectors;
import javax.annotation.CheckForNull;
import org.checkerframework.checker.nullness.qual.Nullable;

/**

   * RandomAccess} support, then this operation is guaranteed to be {@code O(1)}.
   *
   * <p><b>{@code Stream} equivalent:</b> {@link Streams#findLast Streams.findLast(stream).get()}
   *
   * @return the last element of {@code iterable}
   * @throws NoSuchElementException if the iterable is empty
   */
  @ParametricNullness

   * input element is mapped to a key and a stream of values, each of which are put into the
   * resulting {@code Multimap}, in the encounter order of the stream and the encounter order of the
   * streams of values.
   *
   * <p>Example:
   *
   * <pre>{@code
   * static final ImmutableSetMultimap<Character, Character> FIRST_LETTER_MULTIMAP =
   *     Stream.of("banana", "apple", "carrot", "asparagus", "cherry")

   *
   * @since 33.2.0 (available since 21.0 in guava-jre)
   */
  @SuppressWarnings({"AndroidJdkLibsChecker", "Java7ApiChecker"})
  @IgnoreJRERequirement // Users will use this only if they're already using streams.
  @Beta // TODO: b/288085449 - Remove.
  public static <T extends @Nullable Object, R, C, V>
      Collector<T, ?, ImmutableTable<R, C, V>> toImmutableTable(
          Function<? super T, ? extends R> rowFunction,

  private void writeObject(ObjectOutputStream stream) throws IOException {
    stream.defaultWriteObject();
    Serialization.writeMultimap(this, stream);
  }

  @GwtIncompatible // java.io.ObjectInputStream
  @J2ktIncompatible
  private void readObject(ObjectInputStream stream) throws IOException, ClassNotFoundException {
    stream.defaultReadObject();
    int keyCount = stream.readInt();
    if (keyCount < 0) {

   *
   * <p>For example:
   *
   * <pre>{@code
   * Stream.of("foo", "quux", "banana", "elephant")
   *     .collect(least(2, comparingInt(String::length)))
   * // returns {"foo", "quux"}
   * }</pre>
   *
   * <p>This {@code Collector} uses O(k) memory and takes expected time O(n) (worst-case O(n log
   * k)), as opposed to e.g. {@code Stream.sorted(comparator).limit(k)}, which currently takes O(n

 * well.
 *
 * <h3>Java 8+ users</h3>
 *
 * <p>If you are using Java 8+, this class is now obsolete. Most of its functionality is now
 * provided by {@link java.util.stream.Stream Stream} and by {@link Comparator} itself, and the rest
 * can now be found as static methods in our new {@link Comparators} class. See each method below

  /**
   * A collector that converts a stream of zero or one elements to an {@code Optional}.
   *
   * @throws IllegalArgumentException if the stream consists of two or more elements.
   * @throws NullPointerException if any element in the stream is {@code null}.
   * @return {@code Optional.of(onlyElement)} if the stream has exactly one element (must not be

import java.util.Map;
import java.util.NavigableMap;
import java.util.SortedMap;
import java.util.TreeMap;
import java.util.function.BinaryOperator;
import java.util.function.Function;
import java.util.stream.Collector;
import java.util.stream.Collectors;
import javax.annotation.CheckForNull;
import org.checkerframework.checker.nullness.qual.Nullable;

/**

   *
   * @since 33.2.0 (available since 21.0 in guava-jre)
   */
  @SuppressWarnings({"AndroidJdkLibsChecker", "Java7ApiChecker"})
  @IgnoreJRERequirement // Users will use this only if they're already using streams.
  @Beta // TODO: b/288085449 - Remove.
  public static <E> Collector<E, ?, ImmutableSortedMultiset<E>> toImmutableSortedMultiset(
      Comparator<? super E> comparator) {