class Queue:
    def __init__(self):
        self.items = []

    def is_empty(self):
        return self.items == []

    def enqueue(self, item):
        self.items.insert(0, item)

    def dequeue(self):
        return self.items.pop()

    def print_queue(self):
        print(self.items)

q = Queue()
q.enqueue('a')
q.enqueue('b')
q.enqueue('42')
q.print_queue()

q.dequeue()
q.print_queue()

class Node:
  def __init__(self, data, next):
    self.data = data
    self.next = next

class Node:
    def __init__(self, data, next):
        self.data = data
        self.next = next

class LinkedList:
    def __init__(self):
        self.head = None
    
    def add_at_front(self, data):
        self.head = Node(data, self.head)      

    def add_at_end(self, data):
        if not self.head:
            self.head = Node(data, None)
            return
        curr = self.head
        while curr.next:
            curr = curr.next
        curr.next = Node(data, None)

    def get_last_node(self):
        n = self.head
        while(n.next != None):
            n = n.next
        return n.data

    def is_empty(self):
        return self.head == None

    def print_list(self):
        n = self.head
        while n != None:
            print(n.data, end = " => ")
            n = n.next
        print()


s = LinkedList()
s.add_at_front(5)
s.add_at_end(8)
s.add_at_front(9)

s.print_list()
print(s.get_last_node())

// Static Integer Array
int arr[5] = {1, 2, 3, 4, 5};

// Static Integer Array
int arr[5] = {1, 2, 3, 4, 5};

// Static Array
int[] arr = { 1, 2, 3, 4, 5 };

import array
# Static Array
arr = array.array('i', [1, 2, 3, 4, 5])

// Static array
int[] arr = { 1, 2, 3, 4, 5 };

let arr[] = {1, 2, 3, 4, 5}

// Dynamic Integer Array
int* arr = new int[5];

// Dynamic Integer Array
int* arr = malloc(sizeof(int) * 5);

// Dynamic Integer Array
ArrayList<Integer> arr = new ArrayList<>();

# Dynamic Array
arr = []

// Dynamic Integer Array
int[] arr = new int[5];

// Dynamic Array
let arr = new Array(5);

int arr[] = { 1, 2, 3, 4, 5 };
int len = sizeof(arr) / sizeof(arr[0]);
// Traversing over arr[]
for (int i = 0; i < len; i++) {
    printf("%d ", arr[i]);
}

int arr[] = { 1, 2, 3, 4, 5 };
// Traversing over arr[]
for (int i = 0; i < arr.length; i++) {
    System.out.print(arr[i] + " ");
}

import array
arr = array.array('i', [1, 2, 3, 4, 5])
# Traversing over arr[]
for x in arr:
    print(x, end=" ")

int[] arr = { 1, 2, 3, 4, 5 };
// Traversing over arr[]
for (int i = 0; i < arr.Length; i++)
    Console.Write(" " + arr[i]);

let arr = [1, 2, 3, 4, 5]
// Traversing over arr[]
for (let x of arr)
    console.log(x)

int arr[] = { 1, 2, 3, 4, 5 };
int len = sizeof(arr) / sizeof(arr[0]);
// Traversing over arr[]
for (int i = 0; i < len; i++) {
    cout << arr[i] << " ";
}

// Function to insert element
// at a specific position
void insertElement(int arr[], int n, int x, int pos)
{
    // shift elements to the right
    // which are on the right side of pos
    for (int i = n - 1; i >= pos; i--)
        arr[i + 1] = arr[i];
 
    arr[pos] = x;
}

// Function to insert element
// at a specific position
void insertElement(int arr[], int n, int x, int pos)
{
    // shift elements to the right
    // which are on the right side of pos
    for (int i = n - 1; i >= pos; i--)
        arr[i + 1] = arr[i];

    arr[pos] = x;
}

static void insertElement(int arr[], int n, int x, int pos)
{
    // shift elements to the right
    // which are on the right side of pos
    for (int i = n - 1; i >= pos; i--)
        arr[i + 1] = arr[i];
    arr[pos] = x;
}

# python Program to Insert an element
# at a specific position in an Array

def insertElement(arr, n, x, pos):

    # shift elements to the right
    # which are on the right side of pos
    for i in range(n-1, pos-1, -1):
        arr[i + 1] = arr[i]

    arr[pos] = x

static void insertElement(int[] arr, int n, int x, int pos)
{
    // shift elements to the right
    // which are on the right side of pos
    for (int i = n - 1; i >= pos; i--)
        arr[i + 1] = arr[i];
    arr[pos] = x;
}

// javascript Program to Insert an element
// at a specific position in an Array
function insertElement(arr, n, x, pos)
{
    // shift elements to the right
    // which are on the right side of pos
    var i = n - 1;
    for (i; i >= pos; i--)
    {
        arr[i + 1] = arr[i];
    }
    arr[pos] = x;
}

// To search a key to be deleted
int findElement(int arr[], int n, int key);

// Function to delete an element
int deleteElement(int arr[], int n, int key)
{
    // Find position of element to be deleted
    int pos = findElement(arr, n, key);

    if (pos == -1) {
        cout << "Element not found";
        return n;
    }

    // Deleting element
    int i;
    for (i = pos; i < n - 1; i++)
        arr[i] = arr[i + 1];

    return n - 1;
}

// Function to implement search operation
int findElement(int arr[], int n, int key)
{
    int i;
    for (i = 0; i < n; i++)
        if (arr[i] == key)
            return i;
    // Return -1 if key is not found
    return -1;
}

// C program to implement delete operation in a
// unsorted array
#include <stdio.h>
 
// To search a key to be deleted
int findElement(int arr[], int n, int key);
 
// Function to delete an element
int deleteElement(int arr[], int n, int key)
{
    // Find position of element to be deleted
    int pos = findElement(arr, n, key);
 
    if (pos == -1) {
        printf("Element not found");
        return n;
    }
 
    // Deleting element
    int i;
    for (i = pos; i < n - 1; i++)
        arr[i] = arr[i + 1];
 
    return n - 1;
}
 
// Function to implement search operation
int findElement(int arr[], int n, int key)
{
    int i;
    for (i = 0; i < n; i++)
        if (arr[i] == key)
            return i;
     // Return -1 if key is not found
    return -1;
}

from array import array

# Function to search for a key in the array
def findElement(arr, n, key):
    for i in range(n):
          # Return the index if key is found
        if arr[i] == key:
            return i
    # Return -1 if key is not found
    return -1  

# Function to delete an element from the array
def deleteElement(arr, n, key):
    # Find position of element to be deleted
    pos = findElement(arr, n, key)

    if pos == -1:
        print("Element not found")
        return n

    # Deleting element
    for i in range(pos, n - 1):
        arr[i] = arr[i + 1]

    return n - 1

int findElement(int[] arr, int n, int key)
{

    int i;
    for (i = 0; i < n; i++)
        if (arr[i] == key)
            return i;

    return -1;
}

// Function to delete an element
int deleteElement(int[] arr, int n, int key)
{
    // Find position of element
    // to be deleted
    int pos = findElement(arr, n, key);

    if (pos == -1) {
        Console.WriteLine("Element not found");
        return n;
    }

    // Deleting element
    int i;
    for (i = pos; i < n - 1; i++)
        arr[i] = arr[i + 1];

    return n - 1;
}

// function to search a key to
    // be deleted
    static int findElement(int arr[], int n, int key)
    {
        int i;
        for (i = 0; i < n; i++)
            if (arr[i] == key)
                return i;
         // Return -1 if key is not found
        return -1;
    }
 
    // Function to delete an element
    static int deleteElement(int arr[], int n, int key)
    {
        // Find position of element to be
        // deleted
        int pos = findElement(arr, n, key);
 
        if (pos == -1) {
            System.out.println("Element not found");
            return n;
        }
 
        // Deleting element
        int i;
        for (i = pos; i < n - 1; i++)
            arr[i] = arr[i + 1];
 
        return n - 1;
    }

// function to search a key to  be deleted
function findElement(arr,n,key)
{
    let i;
    for (i = 0; i < n; i++)
        if (arr[i] == key)
            return i;
    return -1;
} 
     
// Function to delete an element
function deleteElement(arr,n,key)
{
    // Find position of element to be deleted
    let pos = findElement(arr, n, key);
      
    if (pos == -1)
    {
        document.write("Element not found");
        return n;
    }
    // Deleting element
    let i;
    for (i = pos; i< n - 1; i++)
        arr[i] = arr[i + 1];
    return n - 1;
}

// Function to implement search operation
int findElement(int arr[], int n, int key)
{
    int i;
    for (i = 0; i < n; i++)
        if (arr[i] == key)
            return i;
 
    // If the key is not found
    return -1;
}

// Function to implement search operation
int findElement(int arr[], int n, int key)
{
    int i;
    for (i = 0; i < n; i++)
        if (arr[i] == key)
            return i;
 
    // If the key is not found
    return -1;
}

// Function to implement search operation
int findElement(int arr[], int n, int key)
{
    for (int i = 0; i < n; i++)
        if (arr[i] == key)
            return i;

    // If the key is not found
    return -1;
}

# Python program for searching in
# unsorted array

def findElement(arr, n, key):
    for i in range(n):
        if (arr[i] == key):
            return i
    # If the key is not found
    return -1

// Function to implement
// search operation
int findElement(int[] arr, int n, int key)
{
    for (int i = 0; i < n; i++)
        if (arr[i] == key)
            return i;

    // If the key is not found
    return -1;
}

// Function to implement search operation 
function findElement( arr, n, key)
{
    let i;
    for (i = 0; i < n; i++)
        if (arr[i] == key)
            return i;
 
    return -1;
}