private IEnumerable <IDiGraph <T, TWeight> > StrongConnect(T vertex)
{
var metadata = _metadataLookup[vertex];
metadata.Index = _index;
metadata.LowLink = _index;
_index += 1;
_stack.Push(vertex);
metadata.OnStack = true;
foreach (var outEdge in _graph.GetOutgoingEdges(vertex))
{
var targetVertex = outEdge.TargetVertex;
var outMetadata = _metadataLookup[targetVertex];
if (outMetadata.Index == -1)
{
foreach (var result in StrongConnect(targetVertex))
{
yield return(result);
}
}
if (outMetadata.OnStack)
{
metadata.LowLink = Math.Min(metadata.LowLink, outMetadata.LowLink);
}
}
if (metadata.LowLink != metadata.Index)
{
yield break;
}
IDiGraph <T, TWeight> componentGraph = new DiGraph <T, TWeight>(_graph.DefaultEdgeWeight);
T wVertex;
do
{
wVertex = _stack.Pop();
var stackNodeMetadata = _metadataLookup[wVertex];
stackNodeMetadata.OnStack = false;
componentGraph.AddVertex(wVertex);
} while (!EqualityComparer <T> .Default.Equals(vertex, wVertex));
var filteredEdges = componentGraph.Vertices
.SelectMany(v => _graph.GetOutgoingEdges(v))
.Where(e => componentGraph.Vertices.Contains(e.SourceVertex))
.Where(e => componentGraph.Vertices.Contains(e.TargetVertex));
foreach (var edge in filteredEdges)
{
componentGraph.AddEdge(edge.SourceVertex, edge.TargetVertex, edge.Weight);
}
yield return(componentGraph);
}