QuickGraph - is there algorithm for find all parents (up to root vertex's) of a set of vertex's

Question

In QuickGraph - is there algorithm for find all parents (up to root vertex\'s) of a set of vertex\'s. In other words all vertex\'s which have somewhere under them (on the w

Answer 1

Here's what I've used to accomplish a predecessor search on a given vertex:

IBidirectionalGraph> CreateGraph(int vertexCount)
{
    BidirectionalGraph> graph = new BidirectionalGraph>(true);
    for (int i = 0; i < vertexCount; i++)
        graph.AddVertex(i);

    for (int i = 1; i < vertexCount; i++)
        graph.AddEdge(new Edge(i - 1, i));

    return graph;
}

static public void Main()
{
    IBidirectionalGraph> graph = CreateGraph(5);

    var dfs = new DepthFirstSearchAlgorithm>(graph);            
    var observer = new VertexPredecessorRecorderObserver>();

    using (observer.Attach(dfs)) // attach, detach to dfs events
        dfs.Compute();

    int vertexToFind = 3;
    IEnumerable> edges;
    if (observer.TryGetPath(vertexToFind, out edges))
    {
        Console.WriteLine("To get to vertex '" + vertexToFind + "', take the following edges:");
        foreach (IEdge edge in edges)
            Console.WriteLine(edge.Source + " -> " + edge.Target);
    }
}

Note that if you know your root beforehand, you can specify it in the dfs.Compute() method (i.e. dfs.Compute(0)).

-Doug