private readonly bool[] _marked; // marked[v] = is there an s->v path?
/// <summary>
/// Computes the vertices reachable from the source vertex <tt>s</tt> in the digraph <tt>G</tt>.
/// </summary>
/// <param name="g">g the digraph</param>
/// <param name="s">s the source vertex</param>
public NonrecursiveDirectedDFS(Digraph g, int s)
{
_marked = new bool[g.V];
// to be able to iterate over each adjacency list, keeping track of which
// vertex in each adjacency list needs to be explored next
var adj = new IEnumerator <Integer> [g.V];
for (var v = 0; v < g.V; v++)
{
adj[v] = g.Adj(v).GetEnumerator();
}
// depth-first search using an explicit stack
var stack = new Collections.Stack <Integer>();
_marked[s] = true;
stack.Push(s);
while (!stack.IsEmpty())
{
int v = stack.Peek();
if (adj[v].MoveNext())
{
int w = adj[v].Current;
// StdOut.printf("check %d\n", w);
if (!_marked[w])
{
// discovered vertex w for the first time
_marked[w] = true;
// edgeTo[w] = v;
stack.Push(w);
// StdOut.printf("dfs(%d)\n", w);
}
}
else
{
// StdOut.printf("%d done\n", v);
stack.Pop();
}
}
}
private readonly bool[] _marked; // marked[v] = is there an s->v path?
#endregion Fields
#region Constructors
/// <summary>
/// Computes the vertices reachable from the source vertex <tt>s</tt> in the digraph <tt>G</tt>.
/// </summary>
/// <param name="g">g the digraph</param>
/// <param name="s">s the source vertex</param>
public NonrecursiveDirectedDFS(Digraph g, int s)
{
_marked = new bool[g.V];
// to be able to iterate over each adjacency list, keeping track of which
// vertex in each adjacency list needs to be explored next
var adj = new IEnumerator<Integer>[g.V];
for (var v = 0; v < g.V; v++)
adj[v] = g.Adj(v).GetEnumerator();
// depth-first search using an explicit stack
var stack = new Collections.Stack<Integer>();
_marked[s] = true;
stack.Push(s);
while (!stack.IsEmpty())
{
int v = stack.Peek();
if (adj[v].MoveNext())
{
int w = adj[v].Current;
// StdOut.printf("check %d\n", w);
if (!_marked[w])
{
// discovered vertex w for the first time
_marked[w] = true;
// edgeTo[w] = v;
stack.Push(w);
// StdOut.printf("dfs(%d)\n", w);
}
}
else
{
// StdOut.printf("%d done\n", v);
stack.Pop();
}
}
}