public static NodeClosures Analyse(Node root)
{
var results = new NodeClosures
{
AncestorClosures = new Dictionary<int, HashSet<int>>(),
DescendantClosures = new Dictionary<int, HashSet<int>>()
};
//walk the tree and build the closures lists
var stack = new Stack<Node>();
stack.Push(root);
var route = new Stack<Node>();
while (stack.Count != 0)
{
var current = stack.Pop();
while (route.Any() && !route.Peek().Children.Any(n => n.Id == current.Id))
{
route.Pop();
}
route.Push(current);
AddNodeRelationships(results, current, route);
foreach (var child in current.Children)
{
stack.Push(child);
}
}
return results;
}
private static void AddNodeRelationships(NodeClosures results, Node current, IEnumerable<Node> route)
{
foreach (var node in route)
{
results.AncestorClosures.GetOrCreateValuesList(current.Id).Add(node.Id);
results.DescendantClosures.GetOrCreateValuesList(node.Id).Add(current.Id);
}
}
