static List <int> GetAllLoops(Digraph g)
{
List <int> vertices = g.GetAllVertices();
List <int> loops = new List <int>();
foreach (var vertex in vertices)
{
bool isLoop = IsLoop(g, vertex);
if (isLoop)
{
loops.Add(vertex);
}
}
return(loops);
}
public Digraph(Digraph g) : this(g.V)
{
this.E = g.E;
for (int v = 0; v < g.V; v++)
{
Stack <int> reverse = new Stack <int>();
foreach (int adjacentVertex in g.adjacencyLists[v])
{
reverse.Push(adjacentVertex);
}
foreach (int vertex in reverse)
{
this.adjacencyLists[v].AddLast(vertex);
}
}
}
static void Main(string[] args)
{
Digraph g = new Digraph(10);
g.AddEdge(0, 1);
g.AddEdge(0, 7);
g.AddEdge(7, 7);
g.AddEdge(2, 0);
g.AddEdge(2, 3);
g.AddEdge(2, 4);
g.AddEdge(2, 6);
g.AddEdge(6, 3);
g.AddEdge(3, 3);
g.AddEdge(5, 5);
g.AddEdge(4, 4);
List <int> loops = GetAllLoops(g);
Console.WriteLine("Loop vertices: " + string.Join(", ", loops));
}
static bool IsLoop(Digraph g, int v)
{
// If the adjacency list of vertex v contains itself, this vertex forms a loop.
return(g.GetAdjacentVertices(v).Contains(v));
}