SDE1 Interview Questions at TCS

Implement a function that checks if a string of brackets is valid. Brackets: (), [], {}. Must handle nested brackets.

What is the difference between useEffect with no dependency array, empty array, and with dependencies?

What is the difference between controlled and uncontrolled components? When would you choose uncontrolled?

Explain the difference between a use case diagram and a user story. When would you use each?

Write a function that checks if two strings are anagrams of each other. Handle Unicode characters.

Explain the difference between ArrayList and LinkedList in Java. For a TCS banking project, you need to insert records at the front of a list frequently. Which would you choose and why?

Write a Java program to rotate a matrix 90 degrees clockwise in-place. Explain the transpose-then-reverse approach and why it is O(n2) time with O(1) extra space.

Explain the difference between UNION and UNION ALL. In what scenario does UNION ALL perform significantly better?

Explain the difference between __repr__ and __str__. When is each called? Write a class where they return different things.

Implement a function to check if a number is a power of 2 without using loops or recursion.

What is the difference between ArrayList and LinkedList performance? When would you ever choose LinkedList?

A developer uses List<Object> to store mixed types and casts on retrieval. What are the problems and how would you fix this with Java generics?

Explain why String is immutable in Java. What problem would occur if String were mutable? Give a concrete security example.

What is the difference between WHERE and HAVING clauses? Can you use aggregate functions in WHERE?

Explain the difference between INNER JOIN, LEFT JOIN, and FULL OUTER JOIN. When does the choice affect the result count?

What is the difference between var _default_ = and named exports in React? What's the impact on tree shaking?