I applied online and received a response about two weeks later. There was a phone screen before the onsite interview. The phone interviewer was an Indian gentleman. For this round, half the time was focused on my background and research project. The remaining time, he asked me an algorithm question, which was a matrix problem similar to one listed on LeetCode. I did not provide the optimal solution. Then he asked me some OOP concepts and let me give him a toy example of virtual functions and inheritance. I was told that I passed the phone screen. An onsite interview was scheduled one month later. I made it to the second round but was sent home after that.

The interview in each round followed the same pattern. First, the interviewer asked me to talk about a project listed on my resume, its challenging parts, and how to improve it. Then a technical question was asked. I then had to write code on paper, which made me very uncomfortable. The questions were trivial. One was to check if a string of parentheses was valid. The other was to check if a BST was valid.

Overall, the interview process was not bad, but not comfortable either. Until now, I still don't understand why I was rejected.

Give me an incomplete code which, as a result of a segmentation fault, the interviewer asked me to debug using any debug methods.