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   "cell_type": "markdown",
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   "source": [
    "# Linked Lists"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "\n",
    "\n",
    "### Steps for creating a linked list:\n",
    "1. Create head and tail, initialize with null\n",
    "2. Create a blank node and assign a value to it and reference to null.\n",
    "3. Link head and tail with these nodes\n",
    "\n",
    "[head] -> [node] -> [tail]\n",
    "\n"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 4,
   "metadata": {},
   "outputs": [
    {
     "ename": "AttributeError",
     "evalue": "'NoneType' object has no attribute 'value'",
     "output_type": "error",
     "traceback": [
      "\u001b[0;31m---------------------------------------------------------------------------\u001b[0m",
      "\u001b[0;31mAttributeError\u001b[0m                            Traceback (most recent call last)",
      "\u001b[0;32m<ipython-input-4-75cdb50160b5>\u001b[0m in \u001b[0;36m<module>\u001b[0;34m\u001b[0m\n\u001b[1;32m     24\u001b[0m \u001b[0mlinkedlist\u001b[0m\u001b[0;34m.\u001b[0m\u001b[0mhead\u001b[0m\u001b[0;34m.\u001b[0m\u001b[0mnext\u001b[0m \u001b[0;34m=\u001b[0m \u001b[0mnode_2\u001b[0m\u001b[0;34m\u001b[0m\u001b[0;34m\u001b[0m\u001b[0m\n\u001b[1;32m     25\u001b[0m \u001b[0mlinkedlist\u001b[0m\u001b[0;34m.\u001b[0m\u001b[0mtail\u001b[0m \u001b[0;34m=\u001b[0m \u001b[0mnode_2\u001b[0m\u001b[0;34m\u001b[0m\u001b[0;34m\u001b[0m\u001b[0m\n\u001b[0;32m---> 26\u001b[0;31m \u001b[0mprint\u001b[0m\u001b[0;34m(\u001b[0m\u001b[0;34m[\u001b[0m\u001b[0mnode\u001b[0m\u001b[0;34m.\u001b[0m\u001b[0mvalue\u001b[0m \u001b[0;32mfor\u001b[0m \u001b[0mnode\u001b[0m \u001b[0;32min\u001b[0m \u001b[0mlinkedlist\u001b[0m\u001b[0;34m]\u001b[0m\u001b[0;34m)\u001b[0m\u001b[0;34m\u001b[0m\u001b[0;34m\u001b[0m\u001b[0m\n\u001b[0m",
      "\u001b[0;32m<ipython-input-4-75cdb50160b5>\u001b[0m in \u001b[0;36m<listcomp>\u001b[0;34m(.0)\u001b[0m\n\u001b[1;32m     24\u001b[0m \u001b[0mlinkedlist\u001b[0m\u001b[0;34m.\u001b[0m\u001b[0mhead\u001b[0m\u001b[0;34m.\u001b[0m\u001b[0mnext\u001b[0m \u001b[0;34m=\u001b[0m \u001b[0mnode_2\u001b[0m\u001b[0;34m\u001b[0m\u001b[0;34m\u001b[0m\u001b[0m\n\u001b[1;32m     25\u001b[0m \u001b[0mlinkedlist\u001b[0m\u001b[0;34m.\u001b[0m\u001b[0mtail\u001b[0m \u001b[0;34m=\u001b[0m \u001b[0mnode_2\u001b[0m\u001b[0;34m\u001b[0m\u001b[0;34m\u001b[0m\u001b[0m\n\u001b[0;32m---> 26\u001b[0;31m \u001b[0mprint\u001b[0m\u001b[0;34m(\u001b[0m\u001b[0;34m[\u001b[0m\u001b[0mnode\u001b[0m\u001b[0;34m.\u001b[0m\u001b[0mvalue\u001b[0m \u001b[0;32mfor\u001b[0m \u001b[0mnode\u001b[0m \u001b[0;32min\u001b[0m \u001b[0mlinkedlist\u001b[0m\u001b[0;34m]\u001b[0m\u001b[0;34m)\u001b[0m\u001b[0;34m\u001b[0m\u001b[0;34m\u001b[0m\u001b[0m\n\u001b[0m",
      "\u001b[0;31mAttributeError\u001b[0m: 'NoneType' object has no attribute 'value'"
     ]
    }
   ],
   "source": [
    "class Node:\n",
    "    def __init__(self, value = None):\n",
    "        self.value = value\n",
    "        self.next = None\n",
    "\n",
    "class LinkedList:\n",
    "    def __init__(self):\n",
    "        self.head = None\n",
    "        self.tail = None\n",
    "        self.next = None\n",
    "\n",
    "    def __iter__(self):\n",
    "        node = self.head\n",
    "        while node:\n",
    "            yield node\n",
    "            node = node.next\n",
    "\n",
    "    def __insert__(self, value, location = None):\n",
    "        new_node = Node(value)\n",
    "        if self.head is None:\n",
    "            self.head = new_node\n",
    "            self.tail = new_node\n",
    "\n",
    "        else:\n",
    "\n",
    "            if location == 0:\n",
    "                new_node.next = self.head\n",
    "                self.head = new_node\n",
    "\n",
    "            elif location == -1:\n",
    "                new_node.next = Node\n",
    "                self.tail.next = new_node\n",
    "                self.tail = new_node\n",
    "\n",
    "            else:\n",
    "                temp = self.head\n",
    "                idx = 0\n",
    "                while idx < location -1:\n",
    "                    temp = temp.next\n",
    "                    idx += 1\n",
    "                next_node = temp.next\n",
    "                temp.next = new_node\n",
    "                new_node.next = next_node\n",
    "                \n",
    "                if temp == self.tail:\n",
    "                    self.tail = new_node\n",
    "\n",
    "\n",
    "linkedlist = LinkedList()\n",
    "node_1 = Node(1)\n",
    "node_2 = Node(2)\n",
    "\n",
    "linkedlist.head = node_1\n",
    "linkedlist.head.next = node_2\n",
    "linkedlist.tail = node_2\n",
    "print([node.value for node in linkedlist])"
   ]
  },
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