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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": 1,
   "metadata": {},
   "outputs": [],
   "source": [
    "class Node:\n",
    "    def __init__(self, value):\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"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "### Adding an element inside a linked list"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 2,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "[1, 4, 3, 2, 0]\n"
     ]
    }
   ],
   "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 = None\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",
    "linkedlist.__insert__(1, 1)\n",
    "linkedlist.__insert__(2, 1)\n",
    "linkedlist.__insert__(3, 1)\n",
    "linkedlist.__insert__(4, 1)\n",
    "linkedlist.__insert__(0, 4)\n",
    "\n",
    "print([node.value for node in linkedlist])"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": []
  }
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