private void VisitVertex(Vertex vertex, VisitContext context)
{
Stack <Vertex> walkOrder = new Stack <Vertex>(new [] { vertex });
while (walkOrder.Count > 0)
{
Vertex walkVertex = walkOrder.Pop();
VertexVisitData walkVertexVisitData = context.VisitData[walkVertex];
if (walkVertexVisitData.Color == Color.White)
{
walkVertexVisitData.Color = Color.Gray;
walkVertexVisitData.DiscoverTime = context.Time++;
walkOrder.Push(walkVertex);
Vertex[] neighbors = _graph.GetVertexNeighbors(walkVertex);
foreach (Vertex neighbor in neighbors)
{
VertexVisitData neighborVertexVisitData = context.VisitData[neighbor];
if (neighborVertexVisitData.Color == Color.White)
{
walkOrder.Push(neighbor);
}
}
}
else if (walkVertexVisitData.Color == Color.Gray)
{
walkVertexVisitData.Color = Color.Black;
walkVertexVisitData.FinishTime = context.Time++;
}
}
}
private List <Vertex> VisitVertex(Graph graph, Vertex vertex, VisitContext context)
{
List <Vertex> componentContent = new List <Vertex>();
Stack <Vertex> walkOrder = new Stack <Vertex>(new [] { vertex });
while (walkOrder.Count > 0)
{
Vertex walkVertex = walkOrder.Pop();
VertexVisitData walkVisitedVertexData = context.VisitData[walkVertex];
if (walkVisitedVertexData.Color == Color.White)
{
componentContent.Add(walkVertex);
walkVisitedVertexData.Color = Color.Gray;
Vertex[] neighbors = graph.GetVertexNeighbors(walkVertex);
foreach (Vertex neighbor in neighbors)
{
walkOrder.Push(neighbor);
}
}
}
return(componentContent);
}
private List <List <Vertex> > FindComponentsInTransponesGraph(
Graph transponesGraph,
Dictionary <Vertex, int> vertexFinishTime
)
{
List <List <Vertex> > components = new List <List <Vertex> >();
VisitContext context = new VisitContext
{
Time = 1,
VisitData = _graph
.Vertexes
.ToDictionary(v => v, v => new VertexVisitData(v))
};
Vertex[] orderedVertexes = _graph.Vertexes
.OrderByDescending(v => vertexFinishTime[v])
.ToArray();
foreach (Vertex vertex in orderedVertexes)
{
VertexVisitData visitData = context.VisitData[vertex];
if (visitData.Color == Color.White)
{
List <Vertex> component = VisitVertex(transponesGraph, visitData.Vertex, context);
components.Add(component);
}
}
return(components);
}
public Dictionary <Vertex, VertexVisitData> VisitGraph()
{
VisitContext context = new VisitContext
{
Time = 1,
VisitData = CreateInitalVertexVisitData()
};
foreach (Vertex vertex in _graph.Vertexes)
{
VertexVisitData visitData = context.VisitData[vertex];
if (visitData.Color == Color.White)
{
VisitVertex(visitData.Vertex, context);
}
}
return(context.VisitData);
}