/// <summary>
/// 搜索k近邻点
/// </summary>
/// <param name="p"></param>
/// <param name="k"></param>
/// <returns></returns>
public List <TreeNode> BBFSearchKNearest(Point p, int k)
{
var list = new List <BBFData>(); //
var pq = new MinPQ();
pq.insert(new PQNode(root, 0));
int t = 0;
while (pq.nodes.Count > 0 && t < max_nn_chks)
{
var expl = pq.pop_min_default().data;
expl = Explore2Leaf(expl, p, pq);
var bbf = new BBFData(expl, expl.point.Distance(p));
insert(list, k, bbf);
t++;
}
return(list.Select(l => l.data).ToList());
}