Using WebSocket allows real-time communication between clients and the server, making it ideal for notifying users when someone is typing. setTimeout and clearTimeout are more suitable for handling delays and timeouts, not real-time updates. AJAX polling introduces unnecessary overhead and delays. The oninput event listener is used for detecting input changes, not real-time status updates.

Merge sort is a classic example of a divide and conquer algorithm, where the sorting process involves dividing the array into smaller subarrays, sorting them individually, and then merging them back together in sorted order.

Scrum is an Agile methodology that emphasizes adaptability and customer collaboration over strict planning. It encourages iterative development, frequent feedback, and a focus on delivering value to customers. Scrum teams are self-organizing and cross-functional, with a Scrum Master facilitating the process rather than dictating tasks. This approach promotes flexibility, continuous improvement, and customer satisfaction by responding to changing requirements throughout the development cycle.

Node.js clustering allows applications to utilize multiple CPU cores efficiently by creating child processes (workers) using the cluster module. Each child process runs on a separate core, enabling parallel processing and improved performance. This approach is particularly effective for scaling applications across multiple cores without relying solely on the single-threaded nature of Node.js.

The Repository pattern is commonly used in RESTful APIs to abstract the data access layer and provide a simplified interface for accessing related resources. It helps in organizing code and separating concerns by providing a centralized mechanism for handling database operations related to specific resources.

The useMemo function in React enables developers to memoize components, which optimizes performance by caching the computed value of a function. This avoids unnecessary re-computations and enhances overall efficiency.

The purpose of a circular queue is to avoid the need for resizing the queue when elements are added or removed. In a circular queue, elements are stored in a circular manner, allowing for efficient use of limited memory without the overhead of resizing operations. Additionally, a circular queue supports concurrent access to queue elements, making it suitable for scenarios where multiple processes or threads access the queue simultaneously.

A spanning tree is a subset of the edges of a graph that connects all vertices without any cycles. A minimum spanning tree is specifically the smallest such spanning tree, where the sum of the weights of its edges is minimized. Dijkstra's and Kruskal's algorithms are not specific to defining such subsets in a graph.

Static analysis tools analyze code without executing it, focusing on identifying potential issues, bugs, or violations of coding standards based on code structure, syntax, and patterns. These tools can flag issues such as unused variables, potential memory leaks, or violations of coding conventions like indentation, naming conventions, or code complexity thresholds. They are valuable in ensuring code quality, improving maintainability, and reducing the risk of introducing bugs or vulnerabilities during development. Profiling tools, on the other hand, focus on runtime behavior and performance metrics, coverage tools assess test coverage, and code review involves manual or automated inspection of code by peers or tools.

In a legacy system, normalization involves identifying redundant data and dividing tables to eliminate anomalies such as update, insertion, and deletion anomalies. This is achieved by breaking down data into fewer tables, using foreign keys to establish relationships, and ensuring data integrity. Combining tables or using non-normalized data would not address the underlying issues of redundancy and anomalies.