This is the first round, a telephonic interview. They will ask two questions in 45 minutes. The expectation is to write correct and working code for both questions within that time.

Usually, in telephonic interviews, most companies focus on logic, algorithms, and pseudocode. However, here, the expectation was to write correct code that could be compiled in one go. My advice is to please practice on paper or a notepad before the interview.

For anyone trying for Facebook, my advice is to practice on paper and not on an IDE.

Merge the Intervals