Added linked list challenge.

linked_lists/linked_list/linked_list_solution.ipynb

@@ -4,7 +4,14 @@
    "cell_type": "markdown",
    "metadata": {},
    "source": [
-    "<small><i>This notebook was prepared by [Donne Martin](http://donnemartin.com). Source and license info is on [GitHub](https://bit.ly/code-notes).</i></small>"
+    "<small><i>This notebook was prepared by [Donne Martin](http://donnemartin.com). Source and license info is on [GitHub](https://github.com/donnemartin/coding-challenges).</i></small>"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "# Solution Notebook"
    ]
   },
   {
@@ -26,7 +33,7 @@
    "source": [
     "## Constraints\n",
     "\n",
-    "*Problem statements are often intentionally ambiguous.  Identifying constraints and stating assumptions can help to ensure you code the intended solution.*\n",
+    "*Problem statements are sometimes ambiguous.  Identifying constraints and stating assumptions can help to ensure you code the intended solution.*\n",
     "\n",
     "* Is this a singly or doubly linked list?\n",
     "    * Singly\n",
@@ -181,8 +188,8 @@
    ],
    "source": [
     "%%writefile linked_list.py\n",
-    "\n",
     "class Node(object):\n",
+    "    \n",
     "    def __init__(self, data, next_node=None):\n",
     "        self.next = next_node\n",
     "        self.data = data\n",
@@ -191,6 +198,7 @@
     "        return self.data\n",
     "\n",
     "class LinkedList(object):\n",
+    "    \n",
     "    def __init__(self, head=None):\n",
     "        self.head = head\n",
     "\n",
@@ -287,13 +295,6 @@
     "## Unit Test"
    ]
   },
-  {
-   "cell_type": "markdown",
-   "metadata": {},
-   "source": [
-    "*It is important to identify and run through general and edge cases from the [Test Cases](#Test-Cases) section by hand.  You generally will not be asked to write a unit test like what is shown below.*"
-   ]
-  },
   {
    "cell_type": "code",
    "execution_count": 3,
@@ -305,39 +306,17 @@
      "name": "stdout",
      "output_type": "stream",
      "text": [
-      "Test: insert_to_front on an empty list\n",
-      "Test: insert_to_front on a NULL\n",
-      "Test: insert_to_front general case\n",
-      "Success: test_insert_to_front\n",
-      "\n",
-      "Test: append on an empty list\n",
-      "Test: append a NULL\n",
-      "Test: append general case\n",
-      "Success: test_append\n",
-      "\n",
-      "Test: find on an empty list\n",
-      "Test: find a NULL\n",
-      "Test: find general case with matches\n",
-      "Test: find general case with no matches\n",
-      "Success: test_find\n",
-      "\n",
-      "Test: delete on an empty list\n",
-      "Test: delete a NULL\n",
-      "Test: delete general case with matches\n",
-      "Test: delete general case with no matches\n",
-      "Success: test_delete\n",
-      "\n",
-      "Test: len on an empty list\n",
-      "Test: len general case\n",
-      "Success: test_len\n",
-      "\n"
+      "Overwriting test_linked_list.py\n"
      ]
     }
    ],
    "source": [
+    "%%writefile test_linked_list.py\n",
     "from nose.tools import assert_equal\n",
     "\n",
-    "class Test(object):\n",
+    "\n",
+    "class TestLinkedList(object):\n",
+    "    \n",
     "    def test_insert_to_front(self):\n",
     "        print('Test: insert_to_front on an empty list')\n",
     "        linked_list = LinkedList(None)\n",
@@ -438,13 +417,60 @@
     "        \n",
     "        print('Success: test_len\\n')\n",
     "\n",
-    "if __name__ == '__main__':\n",
-    "    test = Test()\n",
+    "def main():\n",
+    "    test = TestLinkedList()\n",
     "    test.test_insert_to_front()\n",
     "    test.test_append()\n",
     "    test.test_find()\n",
     "    test.test_delete()\n",
-    "    test.test_len()"
+    "    test.test_len()\n",
+    "    \n",
+    "if __name__ == '__main__':\n",
+    "    main()"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 4,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "Test: insert_to_front on an empty list\n",
+      "Test: insert_to_front on a NULL\n",
+      "Test: insert_to_front general case\n",
+      "Success: test_insert_to_front\n",
+      "\n",
+      "Test: append on an empty list\n",
+      "Test: append a NULL\n",
+      "Test: append general case\n",
+      "Success: test_append\n",
+      "\n",
+      "Test: find on an empty list\n",
+      "Test: find a NULL\n",
+      "Test: find general case with matches\n",
+      "Test: find general case with no matches\n",
+      "Success: test_find\n",
+      "\n",
+      "Test: delete on an empty list\n",
+      "Test: delete a NULL\n",
+      "Test: delete general case with matches\n",
+      "Test: delete general case with no matches\n",
+      "Success: test_delete\n",
+      "\n",
+      "Test: len on an empty list\n",
+      "Test: len general case\n",
+      "Success: test_len\n",
+      "\n"
+     ]
+    }
+   ],
+   "source": [
+    "%run -i test_linked_list.py"
    ]
   }
  ],