Untitled

        TreeNode cur = root;
        while (true) {
            if (cur.val <= val) {
              
                if (cur.right != null) {
                    cur = cur.right;
                }
                else {
                    cur.right = new TreeNode(val);
                    break;
                }
            }
            else {
                if (cur.left != null) {
                    cur = cur.left;
                }
                else {
                    cur.left = new TreeNode(val);
                    break;
                }
            }
        }
        return root;