Most informative SWE interview questions?

I try to be different when asking my share of questions in interviews...

My favorite to ask is:

"Tell me about a time you really screwed something up."

This can be a design decision, or may accidentally running "drop table users"...

This is an open ended question. The more experienced interviewees will pivot to how they learned something from it or whatever. I'm just looking for general humility tbh.

If they're nervous or confused, I'll share a few of my stories, like the time I really did drop that users table, or tripped over a power chord in a data center when disaster recovery testing was being done.

What editor do you use? As you dive into your set up, you open up about how much you care about your craft.

Which is not to say that there aren't people who simply don't care about the env they work in, yet are great SWEs: it's just that it reveals the persons attitude, preferences and can get them excited (for better and for worse :)).

I basically just ask questions about hash tables; starting from the concept of associative arrays, down to the implementation of a table specific to a purpose (a minimal perfect hash with a rolling hash function). Generally if a person is trying to be a SWE and doesn't know about associative arrays, they're not going to work out. I don't expect people to answer deep questions about specific hash performance you'd get from a CS grad who studied Knuth; I want to know how you think about a mildly complicated data structure.

Along the way I ask a few questions about bits, which provides some dynamic signal (for example, would this person be good at low-level stuff?)

One I suggested to my team lead was to ask what was a problem or challenge the applicant had been wrestling with recently w.r.t the language or job. I think an organic, open question like this would help to identify what the applicant spent time thinking about and provide insight into their nature as a programmer beyond what leetcode might offer.

I think a similar interesting question: asking for one or several things the applicant dislikes most about the programming language, would be similarly revealing.

YMMV when it comes to people who are smart but not very good talkers, but I think it's better than, say, asking people to sing a song, like some recruiters do.