Solving a programming challenge is not the same as winning the ICPC. And that is what a lot of people here are saying it matters how you use these tools. If you ask developers to solve the very hardest challenges used during the ICPC you are probably going to waste their time and you might miss out on candidates who would have done a good job even if they couldn't solve that challenge. But being asked to have a basic understanding of algorithms, which is what is needed to solve the average challenges, is something that I think should be taken for granted whatever position you are applying to.