Could we change the time of the event please? There are a large number of us who do both of them. This is the first time I see a clash.
I posted a similar post in codechef as well: https://discuss.codechef.com/questions/75130/september-cook-off-clashing-with-codeforces-round-321
But Codechef has been hosting the cookoff at the same time for the last few years. It doesn't make sense for them to change it.