JAWAHARLAL NEHRU TECHNOLOGICAL UNIVERSITY HYDERABAD B.Tech IV DATA STRUCTURES Previous Question Paper (February/March - 2022 - R18)

A singly linked list is a linear data structure where elements, called nodes, are not stored in contiguous memory locations. Each node consists of two parts: a data field and a pointer (or reference) to the next node in the sequence. The last node contains a null pointer, indicating the end of the list.

Operations on a singly linked list:

1. Insertion: To insert a node, we update the pointers. For insertion at the beginning, the new node's next pointer is set to the current head, and the head is updated to the new node. For insertion after a specific node, the new node's next pointer is set to the current node's next, and the current node's next is updated to the new node.
2. Deletion: To delete a node, we traverse the list to find the node preceding the one to be deleted. We then update the preceding node's next pointer to skip the target node, effectively removing it from the chain.
3. Search: Searching involves traversing the list starting from the head node. We compare the data in each node with the target value. If a match is found, the node is returned; if the end of the list is reached without a match, the value is not present.

Example: Consider a list 10 -> 20 -> 30. To insert 15 after 10, we create a node with value 15, set its next pointer to 20, and update the next pointer of the node containing 10 to point to the new node 15, resulting in 10 -> 15 -> 20 -> 30.

Stacks are used in various computing applications due to their Last-In-First-Out (LIFO) property:

• Expression Evaluation: Used for parsing and evaluating mathematical expressions, such as converting infix to postfix notation.
• Function Call Management: The system stack stores activation records, local variables, and return addresses during recursive function calls.
• Undo Mechanisms: Editors and browsers use stacks to keep track of operations or visited pages to enable 'undo' or 'back' functionality.
• Syntax Checking: Compilers use stacks to verify balanced parentheses and delimiters in source code.