Queue.ipynb

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 "cells": [
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "# Queue Implementation using Linked List"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 1,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
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     "text": [
      "Length of node is -> 0\n",
      "Top node is -> None\n",
      "\n",
      "Length of node is -> 4\n",
      "\n",
      "Top node is -> google\n",
      "<- google <- gmail <- check <- facebook \n",
      "\n",
      "Poped node is -> google\n",
      "\n",
      "Top node is -> gmail\n",
      "<- gmail <- check <- facebook \n",
      "\n",
      "Top node is -> gmail\n",
      "\n",
      "Last node is -> facebook\n",
      "\n",
      "Length of node is -> 3\n"
     ]
    }
   ],
   "source": [
    "class node:\n",
    "    def __init__(self,data=None):\n",
    "        self.data=data\n",
    "        self.next=None\n",
    "\n",
    "class Queue:\n",
    "    def __init__(self):\n",
    "        self.first=None;\n",
    "        self.last = None;\n",
    "        self.length=0;\n",
    "        \n",
    "        \n",
    "\n",
    "    def enqueue(self,data):\n",
    "        new_node = node(data)\n",
    "        if(self.length == 0):\n",
    "            self.first = new_node\n",
    "            self.last = new_node\n",
    "        else:\n",
    "            self.last.next = new_node\n",
    "            self.last = new_node\n",
    "            \n",
    "        \n",
    "        self.length +=1\n",
    "        return self\n",
    "    \n",
    "    def dequeue(self):\n",
    "        if(self.length == 0):\n",
    "            return None\n",
    "        if(self.first == self.last):\n",
    "            self.last = None \n",
    "        leaderNode = self.first\n",
    "        self.first = self.first.next\n",
    "        self.length -=1\n",
    "        return leaderNode.data\n",
    "        \n",
    "            \n",
    "    def lookup(self):\n",
    "        cur_node = self.first \n",
    "        if cur_node == None: \n",
    "            print(\"Stack Underflow\") \n",
    "        else:\n",
    "            while(cur_node != None): \n",
    "                print('<-',cur_node.data,end=' ') \n",
    "                cur_node = cur_node.next\n",
    "            print('')\n",
    "            return\n",
    "            \n",
    "            \n",
    "        \n",
    "    def peek(self,position='first'):\n",
    "        if(self.length == 0):\n",
    "            return self.first\n",
    "        else:\n",
    "            if(position == 'first'):\n",
    "                return self.first.data\n",
    "            else:\n",
    "                return self.last.data\n",
    "        \n",
    "    \n",
    "\n",
    "    \n",
    "myQueue = Queue()\n",
    "print('Length of node is ->',myQueue.length)\n",
    "print('Top node is ->',myQueue.peek())\n",
    "myQueue.enqueue('google')\n",
    "myQueue.enqueue('gmail')\n",
    "myQueue.enqueue('check')\n",
    "myQueue.enqueue('facebook')\n",
    "# myQueue.lookup()\n",
    "print('\\nLength of node is ->',myQueue.length)\n",
    "print('\\nTop node is ->',myQueue.peek())\n",
    "myQueue.lookup()\n",
    "print('\\nPoped node is ->',myQueue.dequeue())\n",
    "print('\\nTop node is ->',myQueue.peek())\n",
    "myQueue.lookup()\n",
    "print('\\nTop node is ->',myQueue.peek())\n",
    "print('\\nLast node is ->',myQueue.peek('last'))\n",
    "print('\\nLength of node is ->',myQueue.length)"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "# Queue Implementation using Array"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 13,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "\n",
      "Length of array is -> 0\n",
      " <- google <- gmail <- check <- facebook\n",
      "Length of array is -> 4\n",
      "\n",
      "First in array is -> google\n",
      "\n",
      "dequeue value is -> google\n",
      " <- gmail <- check <- facebook\n",
      "Length of array is -> 3\n",
      "\n",
      "First in array is -> gmail\n"
     ]
    }
   ],
   "source": [
    "class Queue:\n",
    "    def __init__(self):\n",
    "        self.array = []\n",
    "        self.length = 0\n",
    "        \n",
    "# adding the data to the end of the array\n",
    "    def enqueue(self,data):\n",
    "        self.array.append(data)\n",
    "        self.length +=1\n",
    "        return \n",
    "# popping the data to the start of the array    \n",
    "    def dequeue(self):\n",
    "        poped = self.array[0]\n",
    "        self.array.pop(0)\n",
    "        self.length -=1\n",
    "        return poped\n",
    "          \n",
    "# array traverse                \n",
    "    def lookup(self):\n",
    "        for val in self.array:\n",
    "            print(' <-',val,end=\"\")\n",
    "            \n",
    "            \n",
    "        \n",
    "    def peek(self):\n",
    "        return self.array[0]\n",
    "    \n",
    "        \n",
    "        \n",
    "        \n",
    "myQueue = Queue()\n",
    "print('\\nLength of array is ->',myQueue.length)\n",
    "myQueue.enqueue('google')\n",
    "myQueue.enqueue('gmail')\n",
    "myQueue.enqueue('check')\n",
    "myQueue.enqueue('facebook')\n",
    "myQueue.lookup()\n",
    "print('\\nLength of array is ->',myQueue.length)\n",
    "print('\\nFirst in array is ->',myQueue.peek())\n",
    "print('\\ndequeue value is ->',myQueue.dequeue())\n",
    "myQueue.lookup()\n",
    "print('\\nLength of array is ->',myQueue.length)\n",
    "print('\\nFirst in array is ->',myQueue.peek())"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": []
  }
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