private void StrongConnect(
ref int index,
Stack <TarjanNode <TTrigger> > S,
Dictionary <UpdateNode <TTrigger>, TarjanNode <TTrigger> > tarjanInfo,
List <IEnumerable <UpdateNode <TTrigger> > > SCC,
TarjanNode <TTrigger> v)
{
v.Index = index;
v.LowLink = index;
index++;
S.Push(v);
v.OnStack = true;
foreach (var node in GetTriggeredNodes(v.Node.OutgoingTriggers))
{
if (!tarjanInfo.TryGetValue(node, out var w))
{
w = new TarjanNode <TTrigger>(node);
tarjanInfo.Add(node, w);
StrongConnect(ref index, S, tarjanInfo, SCC, w);
v.LowLink = Math.Min(w.LowLink, v.LowLink);
}
else if (w.OnStack)
{
v.LowLink = Math.Min(v.LowLink, w.Index);
}
}
if (v.LowLink == v.Index)
{
var cycle = new List <UpdateNode <TTrigger> >();
while (S.Peek() != v)
{
var w = S.Pop();
w.OnStack = false;
cycle.Add(w.Node);
}
cycle.Add(S.Pop().Node);
if (cycle.Count > 1)
{
SCC.Add(cycle);
}
}
}
private IEnumerable <IEnumerable <UpdateNode <TTrigger> > > FindStronglyConnectedComponents(IEnumerable <TTrigger> triggers)
{
var startNodes = GetTriggeredNodes(triggers);
var SCC = new List <IEnumerable <UpdateNode <TTrigger> > >();
var S = new Stack <TarjanNode <TTrigger> >();
var tarjanInfo = new Dictionary <UpdateNode <TTrigger>, TarjanNode <TTrigger> >();
var index = 0;
foreach (var node in startNodes)
{
if (!tarjanInfo.TryGetValue(node, out var v))
{
v = new TarjanNode <TTrigger>(node);
tarjanInfo.Add(node, v);
StrongConnect(ref index, S, tarjanInfo, SCC, v);
}
}
return(SCC);
}
