public static bool HasCircle(INewGraph graph)
{
var queue = new Queue <IVertex>();
var visited = new HashSet <IVertex>();
var parent = new Dictionary <IVertex, IVertex>();
queue.Enqueue(graph.First());
while (queue.Count > 0)
{
var node = queue.Dequeue();
visited.Add(node);
foreach (var next in graph.GetNeighborVertices(node))
{
if (visited.Contains(next))
{
continue;
}
queue.Enqueue(next);
var px = Find(parent, node);
var py = Find(parent, next);
if (px.Equals(py))
{
return(true);
}
Union(parent, node, next);
}
}
return(false);
}
public static INewGraph Generate(INewGraph graph, IVertex first = null)
{
var ret = graph.Factory.CreateGraph();
var queue = new Queue <IVertex>();
var visited = new HashSet <IVertex>();
queue.Enqueue(first == null ? graph.First() : first);
while (queue.Count > 0)
{
var node = queue.Dequeue();
visited.Add(node);
var v1 = ret.AddVertex(node.Clone() as IVertex);
foreach (var next in graph.GetNeighborVertices(node))
{
if (visited.Contains(next))
{
continue;
}
visited.Add(next);
queue.Enqueue(next);
var v2 = ret.AddVertex(next.Clone() as IVertex);
ret.AddEdge(v1, v2);
}
}
return(ret);
}
protected static void MergeVertexTo(INewGraph graph, IVertex from, IVertex to)
{
LogTool.AssertIsFalse(from.Equals(to));
var fromNeighbors = graph.GetNeighborVertices(from as Common.IVertex).ToList();
foreach (var n in fromNeighbors)
{
var e = graph.GetEdge(from as Common.IVertex, n);
LogTool.AssertNotNull(e);
graph.Remove(e);
if (n.Equals(to))
{
continue;
}
graph.AddEdge(n, to as Common.IVertex);
}
graph.Remove(from as Common.IVertex);
foreach (var n in fromNeighbors)
{
UpdateEdgeCost(graph, n as IVertex);
}
}
