* lesser. For example, {@code [] < [1.0f] < [1.0f, 2.0f] < [2.0f]}.
   *
   * <p>The returned comparator is inconsistent with {@link Object#equals(Object)} (since arrays
   * support only identity equality), but it is consistent with {@link Arrays#equals(float[],
   * float[])}.
   *
   * @since 2.0
   */
  public static Comparator<float[]> lexicographicalComparator() {
    return LexicographicalComparator.INSTANCE;
  }

   * lesser. For example, {@code [] < [1.0] < [1.0, 2.0] < [2.0]}.
   *
   * <p>The returned comparator is inconsistent with {@link Object#equals(Object)} (since arrays
   * support only identity equality), but it is consistent with {@link Arrays#equals(double[],
   * double[])}.
   *
   * @since 2.0
   */
  public static Comparator<double[]> lexicographicalComparator() {
    return LexicographicalComparator.INSTANCE;
  }

   *
   * @since 11.0
   */
  public static <T extends @Nullable Object> Iterable<T> mergeSorted(
      Iterable<? extends Iterable<? extends T>> iterables, Comparator<? super T> comparator) {
    checkNotNull(iterables, "iterables");
    checkNotNull(comparator, "comparator");
    Iterable<T> iterable =
        new FluentIterable<T>() {
          @Override
          public Iterator<T> iterator() {

    }

    @Override
    SortedSet<E> delegate() {
      return (SortedSet<E>) super.delegate();
    }

    @Override
    public @Nullable Comparator<? super E> comparator() {
      synchronized (mutex) {
        return delegate().comparator();
      }
    }

    @Override
    public SortedSet<E> subSet(E fromElement, E toElement) {
      synchronized (mutex) {

import com.google.errorprone.annotations.CanIgnoreReturnValue;
import com.google.errorprone.annotations.DoNotCall;
import java.io.InvalidObjectException;
import java.io.ObjectInputStream;
import java.util.Arrays;
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 org.jspecify.annotations.Nullable;

 */

package com.google.common.collect;

import static com.google.common.collect.CollectPreconditions.checkEntryNotNull;

import com.google.errorprone.annotations.CanIgnoreReturnValue;
import java.util.Comparator;
import java.util.Map;
import java.util.Map.Entry;
import java.util.function.Function;
import java.util.stream.Collector;
import org.jspecify.annotations.Nullable;

/**

   * example, {@code [] < [1] < [1, 2] < [2]}.
   *
   * <p>The returned comparator is inconsistent with {@link Object#equals(Object)} (since arrays
   * support only identity equality), but it is consistent with {@link Arrays#equals(int[], int[])}.
   *
   * @since 2.0
   */
  public static Comparator<int[]> lexicographicalComparator() {
    return LexicographicalComparator.INSTANCE;
  }

  public static <T extends @Nullable Object> UnmodifiableIterator<T> mergeSorted(
      Iterable<? extends Iterator<? extends T>> iterators, Comparator<? super T> comparator) {
    checkNotNull(iterators, "iterators");
    checkNotNull(comparator, "comparator");

    return new MergingIterator<>(iterators, comparator);
  }

  /**
   * An iterator that performs a lazy N-way merge, calculating the next value each time the iterator

  public static <T extends @Nullable Object> UnmodifiableIterator<T> mergeSorted(
      Iterable<? extends Iterator<? extends T>> iterators, Comparator<? super T> comparator) {
    checkNotNull(iterators, "iterators");
    checkNotNull(comparator, "comparator");

    return new MergingIterator<>(iterators, comparator);
  }

  /**
   * An iterator that performs a lazy N-way merge, calculating the next value each time the iterator

 * equality for both keys and values. This may not be the desired behavior for map implementations
 * that use non-standard notions of key equality, such as the entry of a {@code SortedMap} whose
 * comparator is not consistent with {@code equals}.
 *
 * <p>The {@code standard} methods are not guaranteed to be thread-safe, even when all of the
 * methods that they depend on are thread-safe.
 *
 * @author Mike Bostock