reversing_linked_list.ipynb

reversing_linked_list.ipynb

{
  "nbformat": 4,
  "nbformat_minor": 0,
  "metadata": {
    "colab": {
      "name": "reversing_linked_list.ipynb",
      "provenance": [],
      "authorship_tag": "ABX9TyPGeKSJu1pOsS5nm7h7JwyJ",
      "include_colab_link": true
    },
    "kernelspec": {
      "name": "python3",
      "display_name": "Python 3"
    }
  },
  "cells": [
    {
      "cell_type": "markdown",
      "metadata": {
        "id": "view-in-github",
        "colab_type": "text"
      },
      "source": [
        "<a href=\"https://colab.research.google.com/gist/Hamptonjc/e04028f108a0791f9f3c888b1c8a15b9/reversing_linked_list.ipynb\" target=\"_parent\"><img src=\"https://colab.research.google.com/assets/colab-badge.svg\" alt=\"Open In Colab\"/></a>"
      ]
    },
    {
      "cell_type": "markdown",
      "metadata": {
        "id": "PiWLHgXFvPtq"
      },
      "source": [
        "# Reversing a Linked List\n",
        "*because these are real life skillz*"
      ]
    },
    {
      "cell_type": "code",
      "metadata": {
        "id": "mBewLOtEpP0Z"
      },
      "source": [
        "class LinkedList:\n",
        "\n",
        "  class Node:\n",
        "    def __init__(self, value):\n",
        "      self.val = value\n",
        "      self.next = None\n",
        "\n",
        "  def __init__(self, n_nodes):\n",
        "    self.head = self.create_list(n_nodes)\n",
        "    self.print_list()\n",
        "    \n",
        "  def create_list(self, n_nodes):\n",
        "    head = self.Node(1)\n",
        "    node_i = head\n",
        "    for i in range(2,n_nodes+1):\n",
        "      node_i.next = self.Node(i)\n",
        "      node_i = node_i.next\n",
        "    return head\n",
        "\n",
        "  def print_list(self):\n",
        "    head = self.head\n",
        "    while head:\n",
        "      if head.next:\n",
        "        print(head.val, \"->\", end=\" \")\n",
        "      else:\n",
        "        print(head.val, end=\" \")\n",
        "      head = head.next\n",
        "\n",
        "\n",
        "  def reverse(self):\n",
        "    vals = []\n",
        "    node_i = self.head\n",
        "    while node_i:\n",
        "      vals.append(node_i.val)\n",
        "      node_i = node_i.next\n",
        "\n",
        "    node_i = self.head\n",
        "    counter = len(vals)-1\n",
        "    while node_i:\n",
        "      node_i.val = vals[counter]\n",
        "      counter-=1\n",
        "      node_i = node_i.next\n",
        "\n"
      ],
      "execution_count": 34,
      "outputs": []
    },
    {
      "cell_type": "code",
      "metadata": {
        "colab": {
          "base_uri": "https://localhost:8080/"
        },
        "id": "wcPXL9tGqbhP",
        "outputId": "a58e3399-a0b5-436d-83a2-dd0a9e3f7b64"
      },
      "source": [
        "LL1 = LinkedList(n_nodes=7)"
      ],
      "execution_count": 35,
      "outputs": [
        {
          "output_type": "stream",
          "text": [
            "1 -> 2 -> 3 -> 4 -> 5 -> 6 -> 7 "
          ],
          "name": "stdout"
        }
      ]
    },
    {
      "cell_type": "code",
      "metadata": {
        "id": "hp-_sSenrGJS"
      },
      "source": [
        "LL1.reverse()"
      ],
      "execution_count": 36,
      "outputs": []
    },
    {
      "cell_type": "code",
      "metadata": {
        "colab": {
          "base_uri": "https://localhost:8080/"
        },
        "id": "TAZYzz_Mr1mb",
        "outputId": "dc4d147c-d6df-49cc-bdc7-cca2e2a345fe"
      },
      "source": [
        "LL1.print_list()"
      ],
      "execution_count": 38,
      "outputs": [
        {
          "output_type": "stream",
          "text": [
            "7 -> 6 -> 5 -> 4 -> 3 -> 2 -> 1 "
          ],
          "name": "stdout"
        }
      ]
    }
  ]
}