BT Group SSE Interview Questions and Answers

Finding the second maximum value in an array of strings.

• Convert the strings to integers for comparison.

• Sort the array in descending order and return the second element.

• Handle cases where there may be duplicates of the maximum value.

Multithreading can be used to process large files efficiently by dividing the work among multiple threads.

• Divide the file into smaller chunks and assign each chunk to a separate thread for processing.

• Use synchronization techniques to ensure data integrity and avoid race conditions.

• Consider using a thread pool to manage the creation and execution of threads efficiently.

• Example: Reading a large CSV file and processing ea

SOLID is a set of principles for object-oriented programming to make software more maintainable, scalable and robust.

• S - Single Responsibility Principle: A class should have only one reason to change.

• O - Open-Closed Principle: Software entities should be open for extension but closed for modification.

• L - Liskov Substitution Principle: Subtypes must be substitutable for their base types.

• I - Interface Segregation Princip...read more

Liskov Substitution Principle (LSP) states that objects of a superclass should be able to be replaced with objects of its subclasses without affecting the correctness of the program.

• LSP is one of the SOLID principles of object-oriented programming.

• It ensures that the behavior of the program remains consistent when a subclass is used in place of a superclass.

• Violating LSP can lead to unexpected behavior and bugs in the ...read more

Query to delete duplicate rows in a table

• Use the DISTINCT keyword to select unique rows

• Use the GROUP BY clause to group the rows by columns

• Use the HAVING clause to filter out the duplicate rows

• Use the DELETE statement to delete the duplicate rows

Link list implementation

• A linked list is a data structure where each element points to the next one

• It consists of nodes that contain data and a pointer to the next node

• Insertion and deletion are efficient, but random access is not

• Examples include singly linked list, doubly linked list, and circular linked list

SQL injections using plain text query can be of various types.

• Union-based SQL injection

• Error-based SQL injection

• Boolean-based SQL injection

• Time-based SQL injection

• Out-of-band SQL injection