[duped]

> If they can't do Data Structures, are they worthless to Silicon Valley companies?

I think you might be overthinking this - understanding how to model a problem with a data structure is a core competency of any developer. This isn't a "gotcha" question where you need to know union find sets or how to invert a linked list in place.

If the question was rephrased, "design a JSON schema for the state of the board" would you know how to approach it? Because that's essentially what step 1 is asking.