From feb3ed312946b80dd5e075bc0b4792cab0c2fa93 Mon Sep 17 00:00:00 2001
From: Donne Martin <donne.martin@gmail.com>
Date: Wed, 10 Feb 2016 06:30:36 -0500
Subject: [PATCH] Polish add reverse solution.

---
 .../add_reverse/add_reverse_solution.ipynb    | 32 +++++++++----------
 1 file changed, 15 insertions(+), 17 deletions(-)

diff --git a/linked_lists/add_reverse/add_reverse_solution.ipynb b/linked_lists/add_reverse/add_reverse_solution.ipynb
index f3f185f..1d47753 100644
--- a/linked_lists/add_reverse/add_reverse_solution.ipynb
+++ b/linked_lists/add_reverse/add_reverse_solution.ipynb
@@ -73,7 +73,7 @@
     "* Recursive case:\n",
     "    * Set `value` to `carry`\n",
     "    * Add both nodes' `data` to `value`\n",
-    "    * Set the `new_carry` to 1 if `value >= 10, else 0`\n",
+    "    * Set the `carry` to 1 if `value >= 10, else 0`\n",
     "    * Set the `remainder` to `value % 10`\n",
     "    * Create a `node` with the `remainder`\n",
     "    * Set `node.next` to a recursive call on the `next` nodes, passing in the `carry`\n",
@@ -117,31 +117,29 @@
    "source": [
     "class MyLinkedList(LinkedList):\n",
     "\n",
-    "    def __add_reverse__(self, first_node, second_node, carry):\n",
-    "        if type(carry) != int and carry < 0:\n",
-    "            raise ValueError('Invalid int argument: carry')\n",
-    "\n",
+    "    def _add_reverse(self, first_node, second_node, carry):\n",
     "        # Base case\n",
-    "        if first_node is None and second_node is None and carry == 0:\n",
+    "        if first_node is None and second_node is None and not carry:\n",
     "            return None\n",
     "\n",
     "        # Recursive case\n",
     "        value = carry\n",
     "        value += first_node.data if first_node is not None else 0\n",
     "        value += second_node.data if second_node is not None else 0\n",
-    "        new_carry = 1 if value >= 10 else 0\n",
-    "        remainder = value % 10\n",
-    "        node = Node(remainder)\n",
-    "        node.next = self.__add_reverse__(\n",
+    "        carry = 1 if value >= 10 else 0\n",
+    "        value %= 10\n",
+    "        node = Node(value)\n",
+    "        node.next = self._add_reverse(\n",
     "            first_node.next if first_node is not None else None,\n",
     "            second_node.next if first_node is not None else None,\n",
-    "            new_carry)\n",
+    "            carry)\n",
     "        return node\n",
     "\n",
     "    def add_reverse(self, first_list, second_list):\n",
+    "        # See constraints\n",
     "        if first_list is None or second_list is None:\n",
     "            return None\n",
-    "        head = self.__add_reverse__(first_list.head, second_list.head, 0)\n",
+    "        head = self._add_reverse(first_list.head, second_list.head, 0)\n",
     "        return MyLinkedList(head)"
    ]
   },
@@ -244,21 +242,21 @@
  ],
  "metadata": {
   "kernelspec": {
-   "display_name": "Python 2",
+   "display_name": "Python 3",
    "language": "python",
-   "name": "python2"
+   "name": "python3"
   },
   "language_info": {
    "codemirror_mode": {
     "name": "ipython",
-    "version": 2
+    "version": 3
    },
    "file_extension": ".py",
    "mimetype": "text/x-python",
    "name": "python",
    "nbconvert_exporter": "python",
-   "pygments_lexer": "ipython2",
-   "version": "2.7.10"
+   "pygments_lexer": "ipython3",
+   "version": "3.4.3"
   }
  },
  "nbformat": 4,