Can anyone share their approach for problem E and F from the contest ?

We all love AtCoder for it's short,clear-concise high quality problems and unique contest formats. I often find that they come up with great dp problems in their contests.It would be really great if there would be problemset feature with tag functionality (much like codeforces's) so that we could practice there topic-wise too. Therefore,I would like to request AtCoder team(rng_58, snuke and others) to bring us this feature,please.

I was solving some easy problems here ( div2.A/B ) and then I came across this problem which requires nothing but just straightforward implementation. But then I was confused to see the difficulty rating (a recently added feature) for this problem. Is it some kind of bug ?

I was trying to solve this problem form recent Atcoder's beginner contest , but after scratching my head for almost 2h I could not come up with the solution.Then I tried to look for the editorials but this time they were not in English. square1001 has provided solution there which I find uses some kind of DP. Can anyone who has solved this problem explain DP recurrence behind this ?

Hello Codeforces, We are all aware of recent unfortunate incident of CF round 444.And the way people reacted was quite surprising . Problems are set by coders who are also humans like rest of us, so it's natural to occur some errors even if they are tested carefully. What I observed after that incident is , the frequency of contests has been reduced.Without much contests codeforces looks deserted these days. Hence , I appeal to the CF community (specially high rated coders ) to continue the trend and bring some more contest for us. Codeforces has always been known for it's fabulous frequent rounds and it will always be so. In the end, I want to say thanks to all the problem setters out there — trust me you do a great job. Thank you . Wish you a good day ahead.