It's incredibly hard, and would take years for anyone to come up with any algorithm from first principle. Which means that any test of algorithm is a test of knowledge, rather than "how you think" or "being able to reason about subtle behavior in system" etc. You looks good if you already have the knowledge, and you will look like a clown otherwise. That is okay if you also realize that the breadth of CS fundamentals are incredibly broad and everyone only knows a subset of it (ask as many simple things as you can).
My deadlines are measured in months, weeks and in the minimum, days. There is practically no cases where it is in hours, and absolutely no case where it would be 30 minutes. I (We?) have trained myself to work and deal with deadlines/pressures of those standard time frame, which means that if I have only a day to deadline left, my technical mind shut down and it is now thinking about the business to see what should be best done next.
I believe people would feel more pressure at the risk of failing an interview than the risk of their company's product having a downtime
My deadlines are measured in months, weeks and in the minimum, days. There is practically no cases where it is in hours, and absolutely no case where it would be 30 minutes. I (We?) have trained myself to work and deal with deadlines/pressures of those standard time frame, which means that if I have only a day to deadline left, my technical mind shut down and it is now thinking about the business to see what should be best done next.
I believe people would feel more pressure at the risk of failing an interview than the risk of their company's product having a downtime