private static List <int> CalculateFinishingTimes(IDirectedGraphWithReversed <int> graph)
{
var finishedVertices = new List <int>();
var exploredVertices = new HashSet <int>();
foreach (int v in graph.GetVertices())
{
if (!exploredVertices.Contains(v))
{
DfsCalculateFinishingTimes(graph, v, exploredVertices, finishedVertices);
}
}
return(finishedVertices);
}
private static void DfsCalculateFinishingTimes(IDirectedGraphWithReversed <int> graph,
int startVertex,
HashSet <int> exploredVertices,
List <int> finishedVertices)
{
var stack = new Stack <int>();
stack.Push(startVertex);
while (stack.Any())
{
int v = stack.Peek();
if (!exploredVertices.Contains(v))
{
exploredVertices.Add(v);
}
bool hasUnexploredNeighbours = false;
foreach (int w in graph.GetIncomingVertices(v))
{
if (!exploredVertices.Contains(w))
{
hasUnexploredNeighbours = true;
stack.Push(w);
break;
}
}
if (hasUnexploredNeighbours)
{
continue;
}
finishedVertices.Add(stack.Pop());
}
}
public static List <List <int> > FindStronglyConnectedComponents(IDirectedGraphWithReversed <int> graph)
{
List <int> finishingTimesVertices = CalculateFinishingTimes(graph);
return(ComputeStronglyConnectedComponents(graph, finishingTimesVertices));
}
