Western Governors University (WGU) ICSC2100 C949 Data Structures and Algorithms I Practice Exam

A sentinel node is a special type of node used in linked lists to simplify boundary operation implementations, such as adding or removing nodes. By having a sentinel node, which usually acts as a dummy node or marker at the beginning and/or end of the list, you can eliminate the need to check for null (or None) pointers in the list's head or tail when performing operations.

For example, when adding a node to an empty list, the code becomes simpler because you don’t have to handle the case where the list's head is null; you can always perform the same logic regardless of whether that head is null or not. Similarly, when deleting a node, a sentinel provides a consistent reference point, making it easier to maintain the list's integrity without special cases for when you are dealing with the first or last node.

This simplification allows both the implementation and maintenance of linked list operations to become less error-prone and more straightforward, enhancing code readability and reducing the chance for bugs related to boundary conditions.