Hello.
As you already know the round was declared unrated. Firstly, we're extremely sorry that this happened and hope you enjoyed solving the problems regardless.
About what happened, the constraints for B were $$$t = 100$$$ and $$$n = 1000$$$ from the beginning i.e. for more than a month. This problem was supposed to be A initially, so I kept lower constraints than usual to ensure a small queue. At the same time, I didn't want trivial brutes to pass, so $$$n = 1000$$$ seemed like a good choice. Around 1 hour before the contest, a tester reminded me of his earlier feedback about increasing the number of test cases and adding a constraint on the sum of $$$n$$$, which would also make it more clear whether $$$\mathcal{O}(n^2)$$$ solutions should pass or not. At the same instant, I gave him WRITE access on polygon so that he could review all the problems.
Unfortunately, there was some miscommunication on my part leading him to think I have asked him to update the constraints. As a result, he updated the test data and the statement immediately, while I was busy doing last-minute checks. The problem was not intentionally updated during the round; he was under the impression that the contest starts $$$1$$$ hour later than it actually did because of a miscalculation due to Day Light Saving time in his country. As a result, a lot of people were solving problem for old constraints when in fact they were new while some also got RE.
Finally, please understand that this is an explanation of the events and not an excuse. I completely realize that such discussions should happen at least a day before the round, not an hour before. This was a result of many minor lapses, which all unluckily accumulated. I, Anton and, especially, the testers have put a lot of hard work into this round over the last $$$3$$$ months; the testers continuously pushed us to improve the quality of the contest through their honest feedback about the problems and overall difficulty, as well as improvements to the statements. Please do not blame them.
Once again, I am really sorry about this and hope you understand.
So now that we have heard the story, I just want to say this. I feel really disappointed at a large part of the community memeing and blaming all 40 or however many testers it had ("lol testers just want contribution but let a problem with fake constraints through"). Monogon's comments under the announcements were completely on point, yet at the time of writing they are at around 0 points even after my upvote (which suggests a number of downvotes).
Is it so hard to think that maybe something else happened before posting? The fact that there were many testers and none of them noticed already should've been a strong clue that this was a last-minute change.
I myself didn't have perfect information, but I found it pretty disgusting how quick people were to point fingers without any understanding of how this happened.
Yeah, such pointing fingers is not justified considering most commenters didn't have any information.
could not you have increase start time of contest and fix this??
As I said, there was some miscommunication, so I never knew that we are changing the problem. I was busy answering queries when a long queue appeared, all of a sudden. I opened the round server to find out why and got to know about this.
lol, when your rating is 700+ and you solved 2 questions in div2 with 5000 rank and you hear its not rated...
I could not find any meme for this situation guys.
Would it be a rating increase or decrease?
This was my first contest after 6 years and I finally solved one problem and they say it will be unrated. A bit sad :( But that's okay.
WTH, what was you doing in past six years?
Okay, I accept your apologies!
No woman no cry