/**
 * An object that can traverse the nodes that are reachable from a specified (set of) start node(s)
 * using a specified {@link SuccessorsFunction}.
 *
 * <p>There are two entry points for creating a {@code Traverser}: {@link
 * #forTree(SuccessorsFunction)} and {@link #forGraph(SuccessorsFunction)}. You should choose one
 * based on your answers to the following questions:
 *
 * <ol>

        .inOrder();
  }

  private static class RequestSavingGraph implements SuccessorsFunction<Character> {
    private final SuccessorsFunction<Character> delegate;
    final Multiset<Character> requestedNodes = HashMultiset.create();

    RequestSavingGraph(SuccessorsFunction<Character> delegate) {
      this.delegate = checkNotNull(delegate);
    }

    @Override

import com.google.common.base.Predicate;
import com.google.common.base.Splitter;
import com.google.common.collect.ImmutableList;
import com.google.common.collect.ImmutableSet;
import com.google.common.graph.SuccessorsFunction;
import com.google.common.graph.Traverser;
import com.google.common.hash.HashCode;
import com.google.common.hash.HashFunction;
import com.google.errorprone.annotations.CanIgnoreReturnValue;