//note:
//weight = 0 = unvisited
//weight = 1 = temporarily visited
//weight = 2 = permanently visited
private static bool Visit(DirectedGraphNode n)
{
if (n.Weight == 1) //stop all (not a DAG)
{
return(false);
}
if (n.Weight == 2)
{
return(true);
}
n.Weight = 1; //mark node temporarily
foreach (var m in n.Neighbors)
{
if (!Visit(m))
{
return(false); //not a DAG
}
}
//mark node permanently and push it to the stack
n.Weight = 2;
L.Push(n);
return(true);
}
static DirectedGraphNode[] GraphFactory(int[,] matrix)
{
byte asciiSymbol = 65;
DirectedGraphNode[] arr = new DirectedGraphNode[matrix.GetLength(0)];
for (int i = 0; i < arr.Length; i++)
{
DirectedGraphNode node = new DirectedGraphNode(asciiSymbol++);
arr[i] = node;
}
for (int i = 0; i < matrix.GetLength(0); i++)
{
for (int j = 0; j < matrix.GetLength(1); j++)
{
if (matrix[i, j] == 1)
{
arr[i].Neighbors.Add(arr[j]);
}
}
}
return(arr);
}