I applied online for the Scalable Web Engineering program and received a quick reply from a senior software engineer asking for an interview the next day.

First phone interview

The first interviewer was generally very nice and polite.

They conducted the interview by phone, asking me to be by a computer to type in a shared online whiteboard.

• Tell 1-2 minutes about yourself (this was the only question related to my CV in the entire interview process).
• What is the difference between an array and a linked list?
• What is a hash table?
• If you had the worst hash function ever, what is the complexity of lookup?
• How many dates in the 1900s in the format mm/DD/yy are palindromes?

Write a function to reverse a string in the most memory-efficient way (you can code in any language you like).

Follow-up questions to the provided solution:

• What happens if you have an odd-length string?
• What are immutable and mutable strings in Python?

I then had a second phone interview, again with a request for an interview the next day.

Second phone interview

The interviewer had a heavy French accent, which made it difficult to understand his questions and explanations. However, he was generally nice and polite.

In the second interview, there were also no questions about my CV. It consisted of only one programming task, which was more difficult than the previous one.

The programming task was as follows: Travel alerts are displayed on the TripAdvisor website for a given region (e.g., Japan might show that there is an earthquake, etc.). Implement the findBestTravelAlert method (the interviewer pasted some template code in the online whiteboard).

Once the code was done, there were some follow-up questions, such as:

• What is the complexity of the code you have written?
• How can you optimize it? How can you optimize it even further?

After a week, I received an email stating that they would not be continuing with my interview process. In general, the interview process was very fast.

If you are not fresh out of university, you should definitely brush up on your algorithms and data structures before applying for the job. Once they ask for an interview, it will almost always be the next day, so you have very little time to prepare.

Write a memory-efficient string reverse function.