Never have I thought I would be wrongly accused of cheating on Codeforces because it is a big platform with a long reputation. And what makes this situation even worse is that, in fact, I have no possible way to prove that I didn't cheat. Thus when I encountered such a mistake, I felt petrified. I guess the only thing I can do is to write this post to share my problem with all the Codeforces community and let them decide whether there were evident proofs of me cheating or not.

So I would like to share the pair of submissions which, according to the system message I received, "significantly coincide": 114031815 114015470.

The only part which looks similar is the part where dp array is calculated, but those formulas are actually written in the author's solution and, as I see it, couldn't be written any differently (except for defines and code style). If this amount of similarities is enough to accuse people of cheating, then I guess half of the submissions of A problems in every round should be considered copied.

There is one more thing to mention. I don't know if it can be considered as proof, but I would rather mention it than not. 23 minutes before submitting the correct solution, I sent this 114025810. If you compare it with the solution that passed the tests, you will see that the only difference is that I, by mistake, made the inner cycle in the output go till j < n, when it should be j < m. I was trying to find this sneaky mistake for 23 minutes. How could this mistake appear if I copied the correct solution and changed it to look less similar? You decide.

The person who had a "similar" solution to mine sent me a message when he got the system notification that he didn't use any online compilers and resources to share code. I hope he won't mind if you ask him any questions about this situation. His profile is minmise.

P.S. Sorry if this post sounded rude, I just feel pretty emotional right now.

As far as I know, the round duration of 2 hours has been a standard since the very beginning of the Codeforces, therefore all the changes to it may appear to be inconvenient for experienced Codeforces users. But the idea of making rounds a bit longer has come to me many times, so I thought I should share my opinion on the topic.

I guess that it is usually true that if a person is not way ahead of his current division, he doesn't have enough time to even read the last 1-2 problems during the round (if we take an average round with 6-7 problems). But those are the hardest and the most interesting problems of the round, so it is sad to skip them. And this is even sadder to understand, that if you have solved your normal amount of problems and have only 20-30 minutes till the end of the round, it is pretty much impossible to come up with the correct solution for at least one of the following problems and implement it. On the other hand, the slight change of giving the additional 30 minutes could have helped the situation and significantly increased chances to submit it. Also, it gives people who are not so successful in "speedforces" a chance to achieve their potential and gain more rating.

P.S. This was intended to be not a complaint on the format of the rounds, but a suggestion for the improvement. Feel free to criticize it. I appreciate all the feedback on the topic.