After fanatically solving 160+ Project Euler math/programming problems whenever the came out, I’ve accepted an invitation to be part of the testing team. I’ve always thought the problems were very high quality regarding clarity and scale, and now I can confirm that those attributes are quite deliberate based on the discussions I’ve seen leading up to problem publication.

The “one minute rule” is well known at the site and is a requirement that any problem be solvable in under a minute of computation time on a midrange computer. Another rule is that integers larger than 64 bits not be required for the solution; some of my solutions have needed BigInteger, but I guess I missed some optimizations.

One downside to seeing the problems before they are published is that I can’t compete with the few testers who try to be the first to solve each problem as it comes out. That’s OK with me, and besides I don’t see all the problems ahead of time. There are two separate testing teams, so I can compete on some problems if the timing is right.

Cool. So you can now give us hints? I think I’ve used BigInt as well… in the very low percentile that I am…

I loved Project Euler at first, and I solved about 80 problems. But then they all seemed to get too hard. I think it is a pitty that they do not offer a mixture of easy and hard problems. It would be good if there was a forum where subtle hints could be given for the more difficult problems, but the Euler forum is only open to those who have alreday solved the problem. I have reluctantly given up.

I know what you mean, but in the past year or so there has been an effort to mix up the problem difficulty, including a recent batch of five easier problems, 203 – 207.