public static long TotalCost <TData> (this DirectedGraph <TData> graph)
{
var rand = new Random(DateTime.UtcNow.Millisecond);
var pivotVertex = graph.Vertices.ElementAt(rand.Next(0, graph.Vertices.Count - 1));
var totalCost = 0L;
var frontier = new Frontier <TData>(graph);
frontier.AddVertex(pivotVertex);
while (frontier.SeenSoFar() < graph.Vertices.Count)
{
var minOutgoingEdge = frontier.MinEdge();
totalCost += minOutgoingEdge.Metric;
var nextVertex = frontier.ExternalVertex(minOutgoingEdge);
frontier.AddVertex(nextVertex);
}
return(totalCost);
}
public static List <Vertex <TData, TMetric> > FindPath <TData, TMetric>
(Graph <TData, TMetric> graph,
Vertex <TData, TMetric> start,
Vertex <TData, TMetric> finish)
{
var frontier = new Frontier <TData, TMetric>();
frontier.AddVertex(start, null);
while (!frontier.Contains(finish))
{
var shortestEdge = frontier.ShortestEdge();
frontier.AddVertex(shortestEdge.Ending, shortestEdge);
if (!frontier.HasEdges)
{
break;
}
}
//check whether finish node has been found
if (!frontier.Contains(finish))
{
return(null);
}
var path = new List <Vertex <TData, TMetric> >();
for (var current = finish; current != null;)
{
path.Add(current);
var shortestEdge = frontier.EdgeForVertex(current);
current = shortestEdge?.Beginning;
}
path.Reverse();
return(path);
}