Added delete mid challenge.

linked_lists/delete_mid/delete_mid_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",
     "* What if the final node is being deleted, for example a single node list?  Do we make it a dummy with a NULL value?\n",
     "    * Yes\n",
@@ -40,10 +47,10 @@
    "source": [
     "## Test Cases\n",
     "\n",
-    "* Empty list\n",
-    "* Null node to delete\n",
-    "* One node\n",
-    "* Multiple nodes"
+    "* Delete on empty list -> None\n",
+    "* Delete None -> None\n",
+    "* Delete on one node -> [None]\n",
+    "* Delete on multiple nodes"
    ]
   },
   {
@@ -74,11 +81,11 @@
    "cell_type": "code",
    "execution_count": 1,
    "metadata": {
-    "collapsed": true
+    "collapsed": false
    },
    "outputs": [],
    "source": [
-    "%run linked_list.py"
+    "%run ../linked_list/linked_list.py"
    ]
   },
   {
@@ -89,12 +96,8 @@
    },
    "outputs": [],
    "source": [
-    "class Node(object):\n",
-    "    def __init__(self, data):\n",
-    "        self.data = data\n",
-    "        self.next = None\n",
-    "\n",
     "class MyLinkedList(LinkedList):\n",
+    "    \n",
     "    def delete_node(self, node):\n",
     "        if self.head is None:\n",
     "            return\n",
@@ -116,13 +119,6 @@
     "## 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,
@@ -134,17 +130,17 @@
      "name": "stdout",
      "output_type": "stream",
      "text": [
-      "Test: Empty list, null node to delete\n",
-      "Test: One node\n",
-      "Test: Multiple nodes\n",
-      "Success: test_delete_node\n"
+      "Overwriting test_delete_mid.py\n"
      ]
     }
    ],
    "source": [
+    "%%writefile test_delete_mid.py\n",
     "from nose.tools import assert_equal\n",
     "\n",
-    "class Test(object):\n",
+    "\n",
+    "class TestDeleteNode(object):\n",
+    "    \n",
     "    def test_delete_node(self):\n",
     "        print('Test: Empty list, null node to delete')\n",
     "        linked_list = MyLinkedList(None)\n",
@@ -168,9 +164,34 @@
     "        \n",
     "        print('Success: test_delete_node')\n",
     "\n",
+    "def main():\n",
+    "    test = TestDeleteNode()\n",
+    "    test.test_delete_node()\n",
+    "    \n",
     "if __name__ == '__main__':\n",
-    "    test = Test()\n",
-    "    test.test_delete_node()"
+    "    main()"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 4,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "Test: Empty list, null node to delete\n",
+      "Test: One node\n",
+      "Test: Multiple nodes\n",
+      "Success: test_delete_node\n"
+     ]
+    }
+   ],
+   "source": [
+    "%run -i test_delete_mid.py"
    ]
   }
  ],