I applied for a position at Yelp through the university job site. After two days, I received an email from one of their recruiters, asking for a suitable time for a phone interview.

The phone interview was with the recruiter and went well. It was essentially a battery of technical questions checking proficiency. For example, what is the protocol used underneath FTP, what is the size of an int, and other such one-liners. I don't think the recruiter had a technical background; they seemed to be reading from a set of questions. It felt like a filtering process, ensuring a minimum level of proficiency.

After the first interview, I received an email for the next round, which would be a 45-minute Skype interview with one of their engineers. Two days later, around the same time of day as the previous interview, the Skype interview was scheduled.

The interview started with the interviewer describing their profile and job environment. Then, we discussed what I do and what kinds of projects I have completed. I was asked about my experience with various operating systems, specifically my proficiency with Linux and Mac.

I was asked to explain threads and concurrency, which took a considerable amount of time. I was also asked how I would replace a number of text strings in a number of files. Not knowing the sed command did not help me.

Lastly, I was asked a coding question and was asked to write it on a shared pad that the interviewer could see. Although I managed to produce the brute-force solution with some difficulty, I don't think I made the cut. The interview ended well, with the interviewer asking if I had any questions for them.

After two more days, I received an email stating that they would not like to move forward with my application and wished me the best of luck.

This wasn't exactly the most difficult question, but it was the only coding question. I wrote this one in Python, and the interviewer was fine with my choice of language.

The question was that I would be given a string of length 25, consisting of lowercase and uppercase alphabet letters and numbers.

In this string, some uppercase letters were lowercased and sent to me. I had a black box function that returned an integer, something like 13 or 14, indicating the string I received was correct; otherwise, it threw an exception.

My job was to find the right string given a corrupted string.