      "\n",
      "* [Clarifying Questions](#Clarifying-Questions)\n",
      "* [Test Cases](#Test-Cases)\n",
      "* [Algorithm](#Algorithm)\n",
      "* [Code](#Code)"
     ]
    },
    {
     "cell_type": "markdown",
     "metadata": {},
 
</s> remove     "* [Clarifying Questions](#Clarifying-Questions)\n",
 </s> add     "* [Constraints and Assumptions](#Constraints-and-Assumptions)\n", </s> remove     "* Space: O(n), extra space for result and recursion depth"
 </s> add     "* Space: O(n), extra space for result and recursion depth\n",
    "\n",
    "Notes:\n",
    "* Careful with adding if the lists differ\n",
    "    * Only add if a node is not NULL\n",
    "    * Alternatively, we could add trailing zeroes to the smaller list" </s> remove     "    * Return NULL for an invalid operation"
 </s> add     "    * Return NULL for an invalid operation\n",
    "* How large are these numbers--can they fit in memory?\n",
    "    * Yes\n",
    "* Can we assume we already have a linked list class that can be used for this problem?\n",
    "    * Yes" </s> remove    "execution_count": null,
 </s> add    "execution_count": 3,
    "* [Code](#Code)\n",
    "* [Unit Test](#Unit-Test)"
      "\n",
      "* [Clarifying Questions](#Clarifying-Questions)\n",
      "* [Test Cases](#Test-Cases)\n",
      "* [Algorithm](#Algorithm)\n",
    "* [Code](#Code)\n",
    "* [Unit Test](#Unit-Test)"
     ]
    },
    {
     "cell_type": "markdown",
     "metadata": {},
keep keep keep keep replace keep keep keep keep keep
 Reworked notebook: Added more detail to constraints and test cases.  Reworked algorithm discussion and unit test. 
linked-lists/add-reverse.ipynb