Queue Implementation Using Linked List in DSA Python - Interactive Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to create a node with given data.

DSA Python

class Node:
    def __init__(self, data):
        self.data = [1]
        self.next = None

Drag options to blanks, or click blank then click option'

Aself

Bnext

CNode

Ddata

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'next' instead of 'data' for the node's data.

Assigning 'self' or 'Node' instead of the parameter.

The node stores the given data in self.data. So, we assign the parameter data to self.data.

2fill in blank

medium

Complete the enqueue method to add a new node at the end of the queue.

DSA Python

def enqueue(self, data):
    new_node = Node(data)
    if self.rear is None:
        self.front = self.rear = new_node
    else:
        self.rear.next = [1]
        self.rear = new_node

Drag options to blanks, or click blank then click option'

Anew_node

Bself.front

Cself.rear

Ddata

Attempts:

3 left

💡 Hint

Common Mistakes

Assigning rear.next to self.front or self.rear instead of new_node.

Assigning rear.next to data instead of a node.

To add a new node at the end, set the current rear's next pointer to the new node.

3fill in blank

hard

Fix the error in the dequeue method to correctly remove the front node.

DSA Python

def dequeue(self):
    if self.front is None:
        return None
    temp = self.front
    self.front = self.front.[1]
    if self.front is None:
        self.rear = None
    return temp.data

Drag options to blanks, or click blank then click option'

Aprev

Bnext

Cfront

Ddata

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'prev' which does not exist in singly linked list nodes.

Using 'data' or 'front' which are not pointers to the next node.

To remove the front node, update self.front to point to the next node after the current front.

4fill in blank

hard

Fill both blanks to check if the queue is empty.

DSA Python

def is_empty(self):
    return self.[1] is [2]

Drag options to blanks, or click blank then click option'

Afront

Brear

CNone

DTrue

Attempts:

3 left

💡 Hint

Common Mistakes

Checking rear instead of front.

Comparing to True instead of None.

The queue is empty if the front pointer is None.

5fill in blank

hard

Fill all three blanks to implement a method that prints all elements in the queue.

DSA Python

def display(self):
    current = self.[1]
    while current is not [2]:
        print(current.[3], end=' -> ')
        current = current.next
    print('None')

Drag options to blanks, or click blank then click option'

Afront

BNone

Cdata

Drear

Attempts:

3 left

💡 Hint

Common Mistakes

Starting from rear instead of front.

Checking for True instead of None in the loop condition.

Printing 'next' instead of 'data'.

Start from the front node, loop until current is None, and print each node's data.