IMO there's not much difference. Like you aren't going to figure out how to do dynamic programming from first principles, or re-invent the Floyd-Warshall algorithm during a 45 minute interview. Or even come up with the idea of trees on your own. Almost all LC questions are predicated on having heard of and learned about various algorithms and data structures, which really isn't any different from questions predicated on having heard of and learned about various database concepts. We're just used to it because LeetCode is the standard, so everyone grinds it.