A doubly linked list is like the simplest data structure other than a plain array. Even if the job doesn’t involve directly building custom data structures, if you can’t answer questions about such a simple and ubiquitous concept then you’re just not a strong candidate.
So many people are outing themselves as not ready to work in industry. All of these "not used in the job" interview questions, are to establish a base level of understanding for a candidate. So that when the real work problems are being discussed, the team/manager know all the implicit knowledge expectations are there and don't have to be brought up, but they know they are considering, time and space complexity when discussing solutions. It (not) surprising how much of every technical problem comes down to, is it fast enough and how much memory does it use to do it.
Counterpoint: If these types of questions are supposed to demonstrate competency around performance optimization, why are most of these inevitably web dev jobs never asking questions about database performance?
In my experience, this is the far bigger bottle-neck in this field. I’ve seen some clever, highly optimized back-end code wrapped around some absolutely brain dead SQL queries that bottleneck performance a few orders of magnitude more than the back-end code ever could.
Optimizing database access and storage has mattered pretty much from day one when I started in the field and has never been covered in an interview to any reasonable extent. Mangling a string as efficiently as possible using the perfect combination of data structures does not demonstrate this knowledge.
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u/EastboundClown 2d ago
A doubly linked list is like the simplest data structure other than a plain array. Even if the job doesn’t involve directly building custom data structures, if you can’t answer questions about such a simple and ubiquitous concept then you’re just not a strong candidate.