public static List<TreeNode> FindTreeNodes(TreeNode root, TreeNodeFindPredicate predicate) {
List<TreeNode> result = new List<TreeNode>();
FindTreeNodesRecursive(root, predicate, result);
return result;
}
private static void FindTreeNodesRecursive(TreeNode n, TreeNodeFindPredicate predicate, List<TreeNode> arr) {
if (predicate(n))
arr.Add(n);
for (int i = 0; i < n.children.Count; i++)
FindTreeNodesRecursive(n.children[i], predicate, arr);
}