public static void DepthFirstTraversal <T>(this IGraph <T> graph, IGraphNode <T> startingNode, IGraphVisitor <T> visitor)
{
Stack <Pair <IGraphNode <T>, IEnumerator <IGraphEdge <T> > > > openNodes = new Stack <Pair <IGraphNode <T>, IEnumerator <IGraphEdge <T> > > >();
HashSet <IGraphNode <T> > seenNodes = new HashSet <IGraphNode <T> >();
openNodes.Push(new Pair <IGraphNode <T>, IEnumerator <IGraphEdge <T> > >(startingNode, graph.GetEdges(startingNode).GetEnumerator()));
seenNodes.Add(startingNode);
visitor.VisitNodeOpen(startingNode);
while (openNodes.Count > 0)
{
var top = openNodes.Peek();
if (top.Second.MoveNext())
{
IGraphEdge <T> edge = top.Second.Current;
IGraphNode <T> node = edge.node2;
if (!seenNodes.Add(node))
{
continue;
}
openNodes.Push(new Pair <IGraphNode <T>, IEnumerator <IGraphEdge <T> > >(node, graph.GetEdges(node).GetEnumerator()));
visitor.VisitNodeOpen(node);
}
else
{
visitor.VisitNodeClose(openNodes.Pop().First);
}
}
}
public static void BreadthFirstTraversal <T>(this IGraph <T> graph, IGraphNode <T> startingNode, IGraphVisitor <T> visitor)
{
Queue <IGraphNode <T> > openNodes = new Queue <IGraphNode <T> >();
HashSet <IGraphNode <T> > seenNodes = new HashSet <IGraphNode <T> >();
openNodes.Enqueue(startingNode);
seenNodes.Add(startingNode);
while (openNodes.Count > 0)
{
IGraphNode <T> node = openNodes.Dequeue();
visitor.VisitNodeOpen(node);
foreach (IGraphEdge <T> edge in graph.GetEdges(node))
{
if (!seenNodes.Add(edge.node2))
{
continue;
}
openNodes.Enqueue(edge.node2);
}
}
}