Virtusa Interview Question

Can you write a function to reverse a linked list? How would you find the longest substring without repeating characters in a given string? Explain the difference between depth-first search (DFS) and breadth-first search (BFS). When would you use each? What are the differences between SQL and NoSQL databases? Provide examples of when you would use each. Describe a challenging bug you encountered in a project and how you resolved it.