/**
* 广度优先遍历
* **/
public void BreadthFirstTreeWalk(BSTreeNode<T> root, Action<BSTreeNode<T>> func) {
	if (root == null) {
		return;
	}
	List<BSTreeNode<T>> processQueue = new List<BSTreeNode<T>>();
	processQueue.Add(root);
	BSTreeNode<T> current;
	while (processQueue.Count != 0) {
		current = processQueue[0];
		processQueue.RemoveAt(0);
		func(current);
		if (current.left != null) {
			processQueue.Add(current.left);
		}
		if (current.right != null) {
			processQueue.Add(current.right);
		}
	}
	return;
}