import java.io.InputStream;
import java.net.Proxy;
import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.Paths;
import java.util.ArrayList;
import java.util.Collections;
import java.util.Comparator;
import java.util.List;
import java.util.Map;
import java.util.concurrent.TimeUnit;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
import java.util.stream.Collectors;

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 javax.annotation.CheckForNull;

  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

    }

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

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

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

    Arrays.sort(entries, DecreasingCount.INSTANCE);
    return ImmutableMultiset.copyFromEntries(asList(entries));
  }

  private static final class DecreasingCount implements Comparator<Entry<?>> {
    static final Comparator<Entry<?>> INSTANCE = new DecreasingCount();

    @Override
    public int compare(Entry<?> entry1, Entry<?> entry2) {

    Arrays.sort(entries, DecreasingCount.INSTANCE);
    return ImmutableMultiset.copyFromEntries(asList(entries));
  }

  private static final class DecreasingCount implements Comparator<Entry<?>> {
    static final Comparator<Entry<?>> INSTANCE = new DecreasingCount();

    @Override
    public int compare(Entry<?> entry1, Entry<?> entry2) {

import java.io.ObjectInputStream;
import java.io.Serializable;
import java.util.AbstractMap;
import java.util.Arrays;
import java.util.BitSet;
import java.util.Collection;
import java.util.Collections;
import java.util.Comparator;
import java.util.HashSet;
import java.util.Iterator;
import java.util.Map;
import java.util.Map.Entry;
import java.util.Set;
import java.util.SortedMap;
import java.util.function.BinaryOperator;

 * 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

import java.io.ObjectInputStream;
import java.io.Serializable;
import java.util.Arrays;
import java.util.BitSet;
import java.util.Collection;
import java.util.Collections;
import java.util.Comparator;
import java.util.EnumMap;
import java.util.HashSet;
import java.util.Iterator;
import java.util.Map;
import java.util.Set;
import java.util.SortedMap;
import java.util.Spliterator;

    return super.asMap();
  }

  /**
   * {@inheritDoc}
   *
   * <p>Consequently, the values do not follow their natural ordering or the ordering of the value
   * comparator.
   */
  @Override
  public Collection<V> values() {
    return super.values();
  }

  private static final long serialVersionUID = 430848587173315748L;