Chore : Added S1_Stacked_Python.ipynb to repository

Author: syedabdullahbukhari77

Stack/S1_Stacked_Python.ipynb

@@ -0,0 +1,290 @@
+{
+  "nbformat": 4,
+  "nbformat_minor": 0,
+  "metadata": {
+    "colab": {
+      "provenance": []
+    },
+    "kernelspec": {
+      "name": "python3",
+      "display_name": "Python 3"
+    },
+    "language_info": {
+      "name": "python"
+    }
+  },
+  "cells": [
+    {
+      "cell_type": "code",
+      "execution_count": 4,
+      "metadata": {
+        "id": "scionqiNLfUT"
+      },
+      "outputs": [],
+      "source": [
+        "class Node:\n",
+        "  def __init__(self,value):\n",
+        "    self.data = value\n",
+        "    self.next = None"
+      ]
+    },
+    {
+      "cell_type": "code",
+      "source": [
+        "class Node:\n",
+        "    def __init__(self, data):\n",
+        "        self.data = data\n",
+        "        self.next = None\n",
+        "\n",
+        "class Stack:\n",
+        "    def __init__(self):\n",
+        "        self.top = None\n",
+        "\n",
+        "    def is_empty(self):\n",
+        "        return self.top is None\n",
+        "\n",
+        "    def push(self, value):\n",
+        "        new_node = Node(value)\n",
+        "        new_node.next = self.top\n",
+        "        self.top = new_node\n",
+        "\n",
+        "    def peek(self):\n",
+        "        if self.is_empty():\n",
+        "            return 'Stack Empty'\n",
+        "        return self.top.data\n",
+        "\n",
+        "    def pop(self):\n",
+        "        if self.is_empty():\n",
+        "            return 'Stack Empty'\n",
+        "        else:\n",
+        "            data = self.top.data\n",
+        "            self.top = self.top.next  # ❌ Fix: Use assignment (=), not comparison (==)\n",
+        "            return data\n",
+        "    def traverse(self):\n",
+        "        temp = self.top\n",
+        "        while temp:\n",
+        "            print(temp.data)\n",
+        "            temp = temp.next\n"
+      ],
+      "metadata": {
+        "id": "Fd2sQw4YLk1e"
+      },
+      "execution_count": 48,
+      "outputs": []
+    },
+    {
+      "cell_type": "code",
+      "source": [
+        "def reverse_string(text):\n",
+        "    s = Stack()\n",
+        "\n",
+        "    for i in text:\n",
+        "        s.push(i)\n",
+        "\n",
+        "    res = \"\"\n",
+        "\n",
+        "    while not s.is_empty():  # ✅ Use `is_empty()` instead of `isempty()`\n",
+        "        res += s.pop()\n",
+        "\n",
+        "    print(res)\n"
+      ],
+      "metadata": {
+        "id": "bb8dHVcJLmRC"
+      },
+      "execution_count": 49,
+      "outputs": []
+    },
+    {
+      "cell_type": "code",
+      "source": [
+        "def text_editor(text, pattern):\n",
+        "    u = Stack()\n",
+        "    r = Stack()\n",
+        "\n",
+        "    for i in text:\n",
+        "        u.push(i)\n",
+        "\n",
+        "    for i in pattern:\n",
+        "        if not u.is_empty() and i == u.peek():\n",
+        "            data = u.pop()\n",
+        "            r.push(data)  # ✅ Store removed character in redo stack\n",
+        "        else:\n",
+        "            if not r.is_empty():  # ✅ Check redo stack before popping\n",
+        "                data = r.pop()\n",
+        "                u.push(data)  # ✅ Restore character from redo stack\n",
+        "\n",
+        "    res = \"\"\n",
+        "    while not u.is_empty():\n",
+        "        res = u.pop() + res  # ✅ Rebuild string in correct order\n",
+        "\n",
+        "    return res\n"
+      ],
+      "metadata": {
+        "id": "DEXt7fDJLpl5"
+      },
+      "execution_count": 50,
+      "outputs": []
+    },
+    {
+      "cell_type": "code",
+      "source": [
+        "text_editor('america' , 'shut')"
+      ],
+      "metadata": {
+        "colab": {
+          "base_uri": "https://localhost:8080/",
+          "height": 35
+        },
+        "id": "azohncHhPXSY",
+        "outputId": "653e7cf4-37fb-440d-9097-00e59c309467"
+      },
+      "execution_count": 51,
+      "outputs": [
+        {
+          "output_type": "execute_result",
+          "data": {
+            "text/plain": [
+              "'america'"
+            ],
+            "application/vnd.google.colaboratory.intrinsic+json": {
+              "type": "string"
+            }
+          },
+          "metadata": {},
+          "execution_count": 51
+        }
+      ]
+    },
+    {
+      "cell_type": "code",
+      "source": [
+        "s = Stack()"
+      ],
+      "metadata": {
+        "id": "_eDr87U3LtrK"
+      },
+      "execution_count": 52,
+      "outputs": []
+    },
+    {
+      "cell_type": "code",
+      "source": [
+        "s.is_empty()"
+      ],
+      "metadata": {
+        "colab": {
+          "base_uri": "https://localhost:8080/"
+        },
+        "id": "8itEwN69LvnJ",
+        "outputId": "c8eaa31e-c3e7-4408-e642-5983baedc21b"
+      },
+      "execution_count": 53,
+      "outputs": [
+        {
+          "output_type": "execute_result",
+          "data": {
+            "text/plain": [
+              "True"
+            ]
+          },
+          "metadata": {},
+          "execution_count": 53
+        }
+      ]
+    },
+    {
+      "cell_type": "code",
+      "source": [
+        "reverse_string('hello')"
+      ],
+      "metadata": {
+        "colab": {
+          "base_uri": "https://localhost:8080/"
+        },
+        "id": "JZVFp_cDLrg-",
+        "outputId": "f6bee1d9-072e-4d4d-b67e-64fd4f0a3220"
+      },
+      "execution_count": 54,
+      "outputs": [
+        {
+          "output_type": "stream",
+          "name": "stdout",
+          "text": [
+            "olleh\n"
+          ]
+        }
+      ]
+    },
+    {
+      "cell_type": "code",
+      "source": [
+        "s.peek()"
+      ],
+      "metadata": {
+        "colab": {
+          "base_uri": "https://localhost:8080/",
+          "height": 35
+        },
+        "id": "-fyU5ELEL1Wh",
+        "outputId": "e84f389e-c978-4508-9072-5cf1aaaab6d5"
+      },
+      "execution_count": 11,
+      "outputs": [
+        {
+          "output_type": "execute_result",
+          "data": {
+            "text/plain": [
+              "'Stack Empty'"
+            ],
+            "application/vnd.google.colaboratory.intrinsic+json": {
+              "type": "string"
+            }
+          },
+          "metadata": {},
+          "execution_count": 11
+        }
+      ]
+    },
+    {
+      "cell_type": "code",
+      "source": [
+        "s.pop()"
+      ],
+      "metadata": {
+        "colab": {
+          "base_uri": "https://localhost:8080/",
+          "height": 35
+        },
+        "id": "XIA39lHAL3Vx",
+        "outputId": "3c38af68-e1a9-49cf-a52e-4a40068b37b7"
+      },
+      "execution_count": 12,
+      "outputs": [
+        {
+          "output_type": "execute_result",
+          "data": {
+            "text/plain": [
+              "'Stack Empty'"
+            ],
+            "application/vnd.google.colaboratory.intrinsic+json": {
+              "type": "string"
+            }
+          },
+          "metadata": {},
+          "execution_count": 12
+        }
+      ]
+    },
+    {
+      "cell_type": "code",
+      "source": [
+        "s.traverse()"
+      ],
+      "metadata": {
+        "id": "6fP69M2rLx5h"
+      },
+      "execution_count": 13,
+      "outputs": []
+    }
+  ]
+}