A friend told me about their choir's conductor failed attempt to find who was singing the wrong part during rehearsal, and I turned it into a coding problem (yes, I'm _that_ friend). Here's a short blog post about the problem and solution: https://lnkd.in/gQTA9Qjd

The solution (credit to Timothy Johnson) uses a version of binary search that I had never seen before, even after researching the topic extensively for Beyond Cracking the Coding Interview (beyondctci.com). I called it "negative binary search."