private void Dfs(IDiGraph g, int v)
{
onStack[v] = true;
marked[v] = true;
foreach (int w in g.Adj(v))
{
if (HasCycle())
{
return;
}
else if (!marked[w])
{
edgeTo[w] = v;
Dfs(g, w);
}
else if (onStack[w])
{
cycle = new Chapter1.Stack <int>();
for (int x = v; x != w; x = edgeTo[x])
{
cycle.Push(x);
}
cycle.Push(w);
cycle.Push(v);
}
onStack[v] = false;
}
}
public IEnumerable <IDirectedEdge> PathTo(int v)
{
if (!HasPathTo(v))
{
return(null);
}
Chapter1.Stack <IDirectedEdge> path = new Chapter1.Stack <IDirectedEdge>();
for (var e = edgeTo[v]; e != null; e = edgeTo[e.From])
{
path.Push(e);
}
return(path);
}
public override IEnumerable <int> PathTo(int v)
{
if (!HasPathTo(v))
{
return(null);
}
Chapter1.Stack <int> path = new Chapter1.Stack <int>();
for (int x = v; x != S; x = edgeTo[x])
{
path.Push(x);
}
path.Push(S);
return(path);
}
