/// <summary>Gets and returns the successors or predecessors of the given node, omitting paths that correspond to
/// previously visited states and are not better than the existing path.
/// </summary>
/// <param name="parent">The state whose successors or predecessors will be returned.</param>
/// <param name="statesSeen">A dictionary mapping states to the best known path to that state, or null if
/// <see cref="GraphSearchBase{S,A}.EliminateDuplicateStates"/> is false.
/// </param>
/// <param name="reversed">If true, the predecessors of the node will be retrieved. If false, the successors.</param>
/// <returns>Returns the new nodes to add to the queue.</returns>
IEnumerable <Node <StateType, ActionType> > GetNodes(Node <StateType, ActionType> parent,
Dictionary <StateType, Node <StateType, ActionType> > statesSeen,
bool reversed)
{
IEnumerable <StateActionPair <StateType, ActionType> > statePairs =
reversed ? BidiProblem.GetPredecessors(parent.State) : Problem.GetSuccessors(parent.State);
return(statesSeen == null?GetNodes(parent, statePairs)
: GetNonDuplicatedNodes(parent, statePairs, statesSeen));
}
