Ask HN: Does anyone actually use data structures/algorithms at work?

I don't really use them directly, but knowing about them helps me write more performant code. I know to ask questions like "which of the available sort functions is best for data that is mostly sorted" and "what's the best way to navigate this deeply nested object?" They also help you recognize certain patterns and apply known solutions before trying to reinvent the wheel. SO many problems end up being graph problems that have been solved time and time again (and sometimes you can recognize a Traveling Salesman problem before you start ripping your hair out).

Plus, writing algorithms gives you lots of practice with recursion and iteration, and knowing when to use which where. And it's fun! You may not use the knowledge directly, but you do pick up a lot of little useful nuggets for real enterprise development.

I do, sometimes. It comes with trying to optimise things. If you want to make "it" go fast or fit into RAM or whatever, at some point you may have to consider structure deeply. Take the "1 billion row challenge" as a good example of one way data structure considerations naturally emerge.