A reasonable question should never require the candidate to know "just a single trick". Questions that require to combine approaches are far better - they can actually measure if the interviewee can reason about the problem and identify the points for trade-offs.
Btw: if you're interviewing more senior candidates, a code review question is often a good idea. It turns the situation around, from "how do you build this?" to "how would you fix this?"
A reasonable question should never require the candidate to know "just a single trick". Questions that require to combine approaches are far better - they can actually measure if the interviewee can reason about the problem and identify the points for trade-offs.
Btw: if you're interviewing more senior candidates, a code review question is often a good idea. It turns the situation around, from "how do you build this?" to "how would you fix this?"