public boolean isMirrorTree(TreeNode p, TreeNode q) {
		if (p == null && q == null) {
			return true;
		} else if ((p == null && q != null) || (p != null && q == null)) {
			return false;
		} else {
			return (p.val == q.val) && isMirrorTree(p.left, q.right)
					&& isMirrorTree(p.right, q.left);
		}
	}