private void dfs(Digraph g, int v)
{
marked[v] = true;
foreach (var w in g.getAdj(v))
{
if (!marked[w])
dfs(g, w);
}
order.Push(v);
}
private void dfs(Digraph g, int v)
{
marked[v] = true;
onStack[v] = true;
foreach (int w in g.getAdj(v))
{
if(hasCycle()) return;
else if (!marked[w])
{
edgeTo[w] = v;
dfs(g, w);
}
else if (onStack[w])
{
for (int x = v; x != w; x = edgeTo[x])
cycle.Push(x);
cycle.Push(w);
cycle.Push(v);
}
}
onStack[v] = false;
}