UGC-NET CS 2017 November - III Question 22

Introduction

The UGC-NET CS 2017 November - III Question 22 is a question related to computer science and programming. This question requires the programmer to write code to perform certain tasks. The tasks include implementing a linked list, traversing the linked list, and reversing the linked list. The goal of this question is to assess the programming skills and knowledge of the programmer.

Program

## Linked List Implementation and Traversal

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

class LinkedList:
    def __init__(self):
        self.head = None

    def insert(self, data):
        new_node = Node(data)
        if self.head is None:
            self.head = new_node
            return
        current_node = self.head
        while current_node.next is not None:
            current_node = current_node.next
        current_node.next = new_node

    def traverse(self):
        current_node = self.head
        while current_node is not None:
            print(current_node.data, end=" ")
            current_node = current_node.next

```markdown

## Reverse Linked List

```python
def reverse_list(llist):
    prev_node = None
    current_node = llist.head
    while current_node is not None:
        next_node = current_node.next
        current_node.next = prev_node
        prev_node = current_node
        current_node = next_node
    llist.head = prev_node

```markdown

Explanation

The program consists of two parts: linked list implementation and traversal and reverse linked list.

The first part defines two classes, Node and LinkedList. Node is a class that represents a node in a linked list. LinkedList is a class that represents a linked list. The LinkedList class contains an insert method that adds a new node to the end of the linked list, and a traverse method that prints the data of each node in the linked list.

The second part defines a reverse_list function that takes a LinkedList object as input and reverses the order of its nodes. This function uses three variables: prev_node, current_node, and next_node. prev_node refers to the node that comes before the current_node, current_node refers to the node that is being processed, and next_node refers to the node that comes after the current_node. The function uses a while loop to iterate over the nodes in the linked list, and uses the current_node.next, current_node, and prev_node variables to reverse the links between nodes.

Overall, this program demonstrates the programmer's ability to work with linked lists and manipulate them in a variety of ways.