Added append method to linked list. Saved linked list code to file for future reference in linked list problems.

linked-lists/linked-list.ipynb

@@ -4,7 +4,7 @@
    "cell_type": "markdown",
    "metadata": {},
    "source": [
-    "## Problem: Implement a linked list with insert, find, delete, and print methods\n",
+    "## Problem: Implement a linked list with insert, append, find, delete, and print methods\n",
     "\n",
     "* [Clarifying Questions](#Clarifying-Questions)\n",
     "* [Test Cases](#Test-Cases)\n",
@@ -41,6 +41,12 @@
     "* Insert in an empty list\n",
     "* Insert in a list with one element or more elements\n",
     "\n",
+    "### Append\n",
+    "\n",
+    "* Append a NULL\n",
+    "* Append in an empty list\n",
+    "* Insert in a list with one element or more elements\n",
+    "\n",
     "### Find\n",
     "\n",
     "* Find a NULL\n",
@@ -81,6 +87,20 @@
     "* Time: O(1)\n",
     "* Space: O(1), a new node is added\n",
     "\n",
+    "### Append\n",
+    "\n",
+    "* If the data we are inserting is NULL, return\n",
+    "* Create a node with the input data\n",
+    "* If this is an empty list\n",
+    "    * Assign the head to the node\n",
+    "* Else\n",
+    "    * Iterate to the end of the list\n",
+    "    * Set the final node's next to the new node\n",
+    "\n",
+    "Complexity:\n",
+    "* Time: O(n)\n",
+    "* Space: O(1), a new node is added\n",
+    "\n",
     "### Find\n",
     "\n",
     "* If data we are finding is NULL, return\n",
@@ -132,6 +152,8 @@
    },
    "outputs": [],
    "source": [
+    "%%writefile linked_list.py\n",
+    "\n",
     "class Node(object):\n",
     "    def __init__(self, data):\n",
     "        self.next = None\n",
@@ -143,7 +165,7 @@
     "class LinkedList(object):\n",
     "    def __init__(self, head):\n",
     "        self.head = head\n",
-    "\n",
+    "    \n",
     "    def insert_to_front(self, data):\n",
     "        if data is None:\n",
     "            return\n",
@@ -154,6 +176,18 @@
     "            node.next = self.head\n",
     "            self.head = node\n",
     "            \n",
+    "    def append(self, data):\n",
+    "        if data is None:\n",
+    "            return\n",
+    "        node = Node(data)\n",
+    "        if self.head is None:\n",
+    "            self.head = node\n",
+    "        else:\n",
+    "            curr_node = self.head\n",
+    "            while curr_node.next is not None:\n",
+    "                curr_node = curr_node.next\n",
+    "            curr_node.next = node\n",
+    "            \n",
     "    def find(self, data):\n",
     "        if data is None:\n",
     "            return\n",
@@ -188,6 +222,17 @@
     "            curr_node = curr_node.next"
    ]
   },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "metadata": {
+    "collapsed": true
+   },
+   "outputs": [],
+   "source": [
+    "%run linked_list.py"
+   ]
+  },
   {
    "cell_type": "code",
    "execution_count": null,
@@ -210,6 +255,28 @@
     "linked_list.print_list()"
    ]
   },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [],
+   "source": [
+    "# Test append\n",
+    "# Insert in an empty list\n",
+    "linked_list = LinkedList(None)\n",
+    "linked_list.append(10)\n",
+    "linked_list.print_list()\n",
+    "# Insert a NULL\n",
+    "linked_list.append(None)\n",
+    "linked_list.print_list()\n",
+    "# Insert in a list with one element or more elements\n",
+    "linked_list.append('a')\n",
+    "linked_list.append('bc')\n",
+    "linked_list.print_list()"
+   ]
+  },
   {
    "cell_type": "code",
    "execution_count": null,