return new MultimapBuilderWithKeys<@Nullable Object>() {
      @Override
      <K extends @Nullable Object, V extends @Nullable Object> Map<K, Collection<V>> createMap() {
        return Platform.newHashMapWithExpectedSize(expectedKeys);
      }
    };
  }

  /**
   * Uses a hash table to map keys to value collections.
   *
   * <p>The collections returned by {@link Multimap#keySet()}, {@link Multimap#keys()}, and {@link

    return new MultimapBuilderWithKeys<@Nullable Object>() {
      @Override
      <K extends @Nullable Object, V extends @Nullable Object> Map<K, Collection<V>> createMap() {
        return Platform.newHashMapWithExpectedSize(expectedKeys);
      }
    };
  }

  /**
   * Uses a hash table to map keys to value collections.
   *
   * <p>The collections returned by {@link Multimap#keySet()}, {@link Multimap#keys()}, and {@link

    return new LinkedListMultimap<>(multimap);
  }

  LinkedListMultimap() {
    this(12);
  }

  private LinkedListMultimap(int expectedKeys) {
    keyToKeyList = Platform.newHashMapWithExpectedSize(expectedKeys);
  }

  private LinkedListMultimap(Multimap<? extends K, ? extends V> multimap) {
    this(multimap.keySet().size());
    putAll(multimap);
  }

  /**

      return true; // Optimization for the undirected case: at least one cycle must exist.
    }

    Map<Object, NodeVisitState> visitedNodes =
        Maps.newHashMapWithExpectedSize(graph.nodes().size());
    for (N node : graph.nodes()) {
      if (subgraphHasCycle(graph, visitedNodes, node)) {
        return true;
      }
    }
    return false;
  }

  /**

    return new LinkedListMultimap<>(multimap);
  }

  LinkedListMultimap() {
    this(12);
  }

  private LinkedListMultimap(int expectedKeys) {
    keyToKeyList = Platform.newHashMapWithExpectedSize(expectedKeys);
  }

  private LinkedListMultimap(Multimap<? extends K, ? extends V> multimap) {
    this(multimap.keySet().size());
    putAll(multimap);
  }

  /**