* to streams.
 *
 * @author Chris Povirk
 * @author Mike Bostock
 * @author Jared Levy
 * @since 2.0
 */
@GwtCompatible
public final class Collections2 {
  private Collections2() {}

  /**
   * Returns the elements of {@code unfiltered} that satisfy a predicate. The returned collection is
   * a live view of {@code unfiltered}; changes to one affect the other.
   *

 * to streams.
 *
 * @author Chris Povirk
 * @author Mike Bostock
 * @author Jared Levy
 * @since 2.0
 */
@GwtCompatible
public final class Collections2 {
  private Collections2() {}

  /**
   * Returns the elements of {@code unfiltered} that satisfy a predicate. The returned collection is
   * a live view of {@code unfiltered}; changes to one affect the other.
   *

    assertPermutationsCount(1, Collections2.permutations(Collections.<Integer>emptyList()));
    assertPermutationsCount(1, Collections2.permutations(newArrayList(1)));
    assertPermutationsCount(2, Collections2.permutations(newArrayList(1, 2)));
    assertPermutationsCount(6, Collections2.permutations(newArrayList(1, 2, 3)));
    assertPermutationsCount(5040, Collections2.permutations(newArrayList(1, 2, 3, 4, 5, 6, 7)));

    assertPermutationsCount(1, Collections2.permutations(Collections.<Integer>emptyList()));
    assertPermutationsCount(1, Collections2.permutations(newArrayList(1)));
    assertPermutationsCount(2, Collections2.permutations(newArrayList(1, 2)));
    assertPermutationsCount(6, Collections2.permutations(newArrayList(1, 2, 3)));
    assertPermutationsCount(5040, Collections2.permutations(newArrayList(1, 2, 3, 4, 5, 6, 7)));

        return object != null && Collections2.safeContains(delegate, object);
      }

      @Override
      public boolean containsAll(Collection<?> collection) {
        return standardContainsAll(collection);
      }

      @Override
      public boolean remove(@Nullable Object object) {
        return object != null && Collections2.safeRemove(delegate, object);
      }

      @Override

        return object != null && Collections2.safeContains(delegate, object);
      }

      @Override
      public boolean containsAll(Collection<?> collection) {
        return standardContainsAll(collection);
      }

      @Override
      public boolean remove(@Nullable Object object) {
        return object != null && Collections2.safeRemove(delegate, object);
      }

      @Override

import static com.google.common.collect.Maps.immutableEntry;
import static java.util.Collections.emptyList;
import static java.util.Collections.emptySet;
import static java.util.Collections.unmodifiableList;
import static java.util.Collections.unmodifiableSet;

import com.google.common.annotations.GwtCompatible;
import com.google.common.base.MoreObjects;

import static com.google.common.collect.Maps.immutableEntry;
import static java.util.Collections.emptyList;
import static java.util.Collections.emptySet;
import static java.util.Collections.unmodifiableList;
import static java.util.Collections.unmodifiableSet;

import com.google.common.annotations.GwtCompatible;
import com.google.common.base.MoreObjects;

    }
  }

  public void testRemoveAt_exhaustive() {
    int size = reduceExponentIfGwt(8);
    List<Integer> expected = createOrderedList(size);
    for (Collection<Integer> perm : Collections2.permutations(expected)) {
      for (int i = 0; i < perm.size(); i++) {
        MinMaxPriorityQueue<Integer> q = MinMaxPriorityQueue.create(perm);
        q.removeAtForTesting(i);

    }
  }

  public void testRemoveAt_exhaustive() {
    int size = reduceExponentIfGwt(8);
    List<Integer> expected = createOrderedList(size);
    for (Collection<Integer> perm : Collections2.permutations(expected)) {
      for (int i = 0; i < perm.size(); i++) {
        MinMaxPriorityQueue<Integer> q = MinMaxPriorityQueue.create(perm);
        q.removeAtForTesting(i);