     "source": [
      "## Constraints\n",
      "\n",
      "* Can we assume k is a valid integer?\n",
      "    * Yes\n",
      "* If k = 0, does this return the last element?\n",
      "    * Yes\n",
      "* What happens if k is greater than or equal to the length of the linked list?\n",
      "    * Return None\n",
 
</s> remove     "* Is this a singly or doubly linked list?\n",
    "    * Singly\n",
    "* Is this a circular list?\n",
    "    * No\n",
 </s> add     "* Can we assume this is a non-circular, singly linked list?\n",
    "    * Yes\n", </s> remove     "* Is this a singly or doubly linked list?\n",
    "    * Singly\n",
    "* Is this a circular list?\n",
    "    * No\n",
 </s> add     "* Can we assume this is a non-circular, singly linked list?\n",
    "    * Yes\n",
    "* Can we assume this is a non-circular, singly linked list?\n",
    "    * Yes\n",
     "source": [
      "## Constraints\n",
      "\n",
    "* Can we assume this is a non-circular, singly linked list?\n",
    "    * Yes\n",
      "* Can we assume k is a valid integer?\n",
      "    * Yes\n",
      "* If k = 0, does this return the last element?\n",
      "    * Yes\n",
      "* What happens if k is greater than or equal to the length of the linked list?\n",
      "    * Return None\n",
keep keep add keep keep keep keep keep keep
 Update linked list constraints

Specify singly linked list, non circular.  Also specify the solution fits in memory. 
linked_lists/kth_to_last_elem/kth_to_last_elem_solution.ipynb