Hi Codeforces,
We are missing the hardest problems for the upcoming long challenges. If you have some interesting ideas send us a mail to problem.ideas@codechef.com, or via this form.
Take a look to the following problems to have a feeling of the difficulty.
CUREK, PBOXES, BCYCLES, LVMFFN, MXMN, CNNCT2
We would be very happy to receive problems of other difficulty levels too.
There are some problems in the queue for the easier problems, but if the idea is very original it can be quickly moved to the top.