public int getDepth(TreeNode node, int depth) {
		int leftDepth = depth;
		int rightDepth = depth;
		if (null != node.left)
			leftDepth = getDepth(node.left, leftDepth + 1);
		if (null != node.right)
			rightDepth = getDepth(node.right, rightDepth + 1);
		return leftDepth > rightDepth ? leftDepth : rightDepth;

	}