I am working on this problem on Kattis. I have been constantly thinking about it for the last 3 hours, but it seems that I am totally hopeless on this problem. Can someone give me some hints?
(I know 3 hours is too short :(. Normally I would only give up if it lasted for a few days, but I am in my urgent self-training period before an NWERC, so I change my plan to solve problems that I am totally hopeless instead of those that are hard but still somehow solvable and I use all this time just to make sure that it is really impossible for me)
Thank you. Happy Coding