While I will say that flood fill is probably too hard for a screener question, I have used it multiple times at work. Sometimes incorrectly, but knowing it help

While I will say that flood fill is probably too hard for a screener question, I have used it multiple times at work. Sometimes incorrectly, but knowing it helped me realize it was incorrect. It is true that I use a hard algorithm maybe 8 times a year. But I need my coworkers to be able to understand them when we do. So that's one part of it. Another major part is having you go into detail about complexity and tradeoffs. Believe it or not most of my co-workers can derrive these things on the fly, not memorized. Others require a little think. The third is algorithms boil down to simple interviews where only a few things can go meta wrong. There are other types of question but they have a lot more failure modes and are even harder to train people to give.