private static void DuplicateGraph(DigraphBase g)
{
for (int i = 0; i < g.V; i++)
{
g.AddEdge(i, i);
foreach (var v in g.Adj(i))
{
g.AddEdge(i, v);
}
}
}
private void DfsVisit(DigraphBase g, int u)
{
_ids[u] = _count;
_vertices[u].Color = Color.Gray;
foreach (var v in g.Adj(u))
{
if (_vertices[v].Color == Color.White)
{
DfsVisit(g, v);
}
}
_vertices[u].Color = Color.Black;
}
private void DfsOrderVisit(DigraphBase g, int u, Stack <int> stack)
{
_vertices[u].Color = Color.Gray;
_vertices[u].D = ++_time;
foreach (var v in g.Adj(u))
{
if (_vertices[v].Color == Color.White)
{
DfsOrderVisit(g, v, stack);
}
}
_vertices[u].F = ++_time;
_vertices[u].Color = Color.Black;
stack.Push(u);
}
private void Dfs(DigraphBase g, Stack <int> vertices)
{
foreach (var vertex in _vertices)
{
vertex.Color = Color.White;
}
foreach (int i in vertices)
{
if (_vertices[i].Color == Color.White)
{
DfsVisit(g, i);
_count++;
}
}
}
public SCC(DigraphBase g)
{
_ids = new int[g.V];
_vertices = new Vertex[g.V];
for (int i = 0; i < g.V; i++)
{
_vertices[i] = new Vertex();
}
Stack <int> vertices = DfsOrder(g);
DigraphBase gt = g.Transpose();
Dfs(gt, vertices);
//call DFS.G/ to compute finishing times u:f for each vertex u
//compute GT
//call DFS.GT/, but in the main loop of DFS, consider the vertices in order of decreasing u:f (as computed in line 1)
//output the vertices of each tree in the depth-first forest formed in line 3 as a separate strongly connected component
}
private Stack <int> DfsOrder(DigraphBase g)
{
foreach (var vertex in _vertices)
{
vertex.Color = Color.White;
}
Stack <int> stack = new Stack <int>();
_time = 0;
for (int i = 0; i < g.V; i++)
{
if (_vertices[i].Color == Color.White)
{
DfsOrderVisit(g, i, stack);
}
}
return(stack);
}