Comment by zelphirkalt

I would rather work with persistent data structures, the least brittle of all, which would also in many cases trivially allow me to parallelize the work, but as far as I can see all the leetcode problems are low level mutation based problems with no clue about functional data structures. Clueless interviewers look to these problems as if they alone epitomized great programming, while they are often inflexible single core stuff, that may not even be appropriate for this day and age any longer.