I applied online.

The interview process was actually good. I was briefed about the entire hiring process in the first email, which stated that I had to do an OA, then a call with an engineer to discuss my approach, and finally a technical round to close the process. I liked their OA; it's unique and practical. It was not time-boxed, although three hours is the average time apparently, and the problem was relatable to their product. Interviewers in both rounds were knowledgeable and warm.

Sigma Computing's evaluation criteria seem like a black box, or they just don't know what they want. It seems like all they need is just one intern, for which they are interviewing hundreds of folks and wasting each one's time. In spite of cracking all the rounds and the interviewers seemingly satisfied with my performance, I shockingly received a rejection after a week. I politely requested feedback twice as I was looking forward to the offer. There was no reply whatsoever. I would have embraced the rejection had they provided me with feedback so that I could tune my process accordingly.

• A filesystem structure-related problem through a CLI interface as inputs. It tested my design, programming, and data-structures skills. There wasn't any time limit as such, but I was expected to finish within three hours, which I did.
• Discussions about my approaches and thought process for the first task. There were a couple of behavioral questions too, which I honestly didn't expect, but the interviewer seemed to have gotten the answers he was looking for, nonetheless. He was nice to discuss and brainstorm along with.
• Coding round for about 45 minutes. I was asked a couple of questions related to random numbers and trees, and later on, I was asked to improve the space complexity. I answered all the questions I was asked, and the interviewer was seemingly convinced.