Create a Circular Singly Linked List in DSA Python - Build from Scratch

Create a Circular Singly Linked List

📖 Scenario: You are building a simple music playlist app. The playlist should loop back to the first song after the last one finishes, so the music never stops.

🎯 Goal: Create a circular singly linked list to represent the playlist where each node contains a song name and points to the next song. The last song should point back to the first song.

📋 What You'll Learn

Create a Node class with data and next attributes

Create a circular singly linked list with exactly three songs: 'Song A', 'Song B', and 'Song C'

Link the last node back to the first node to make the list circular

Print the playlist songs in order, stopping after printing all three songs once

💡 Why This Matters

🌍 Real World

Circular linked lists are useful in applications like music playlists, where the list loops back to the start automatically.

💼 Career

Understanding circular linked lists helps in software development roles involving data structures, game development, and real-time systems.

1

Create the Node class and three nodes

Create a class called Node with an __init__ method that takes data and sets self.data and self.next to None. Then create three nodes called node1, node2, and node3 with data 'Song A', 'Song B', and 'Song C' respectively.

DSA Python

# Define Node class and create three nodes
# Your code here

Hint

Remember to set self.next to None inside the __init__ method.

2

Link the nodes to form a circular list

Link node1.next to node2, node2.next to node3, and node3.next back to node1 to make the list circular.

DSA Python

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

node1 = Node('Song A')
node2 = Node('Song B')
node3 = Node('Song C')

# Link the nodes to form a circular linked list
# Your code here

Hint

Make sure the last node points back to the first node to complete the circle.

3

Create a variable to start at the first node

Create a variable called current and set it to node1 to start traversing the playlist from the first song.

DSA Python

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

node1 = Node('Song A')
node2 = Node('Song B')
node3 = Node('Song C')

node1.next = node2
node2.next = node3
node3.next = node1

# Set current to node1 to start traversal
# Your code here

Hint

This variable will help us move through the playlist starting from the first song.

4

Print all songs in the circular list once

Use a for loop that runs exactly 3 times to print current.data and then move current to current.next in each iteration.

DSA Python

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

node1 = Node('Song A')
node2 = Node('Song B')
node3 = Node('Song C')

node1.next = node2
node2.next = node3
node3.next = node1

current = node1

# Print all songs once using a for loop
# Your code here

Hint

Use a loop that runs 3 times because there are 3 songs. Print the current song and then move to the next.