public static IList <int> GetNodesBreadthFirst(this SimpleGraph graph, int startNode, Func <int, bool> filter, Func <IList <int>, int, bool> terminator)
{
var results = ListPool <int> .Take();
var open = ListPool <int> .Take();
open.Add(startNode);
var currentDepth = 0;
var depthSize = 1;
var nextDepthSize = 0;
while (open.Count > 0)
{
var node = open.Dequeue();
if (filter(node) && !results.Contains(node))
{
results.Add(node);
}
depthSize--;
var numArcs = graph.NumArcsForNode(node);
for (int i = 0; i < numArcs; i++)
{
var neighbour = graph.GetNodeArc(node, i);
if (!open.Contains(neighbour))
{
open.Add(neighbour);
nextDepthSize++;
}
}
// If we've visited all nodes at current depth, get ready for the next depth level.
if (depthSize == 0)
{
currentDepth++;
depthSize = nextDepthSize;
nextDepthSize = 0;
}
// Stop traversal if the termination condition is met.
if (terminator(results, currentDepth))
{
break;
}
}
return(results);
}
/// <summary>
/// Build a SimpleGraph from the temporary graph contained by the builder.
/// </summary>
public SimpleGraph Build()
{
var result = new SimpleGraph(nodes.Count, arcTotal);
int currArc = 0;
for (int i = 0; i < nodes.Count; i++)
{
result.nodes[i] = currArc;
var currNode = nodes[i];
currNode.CopyTo(result.arcs, currArc);
currArc += currNode.Count;
}
return(result);
}
