First of all, I want to clarify that I completed this round entirely independently and did not use any online editors or share my code. I am also very surprised to find that my solution to Problem B matches that of another user.
I can provide the following evidence to clarify this situation:
Regarding my solution approach, I had a clear strategy from the start:
First, I considered invalid cases where n > 1 and either k = 1 or k = n, as these cases cause k to be a boundary and thus cannot be a median under any circumstances. For valid cases, I proceeded by analyzing k based on its parity. If k is even, I can treat k itself as an individual element in the array b, with two subarrays on its left and right, both of odd lengths, ensuring k can serve as a median. If k is odd, it requires at least three elements (an odd number) on either side to make k a median. The optimal approach here is to take the smallest odd number (3) so that k remains the median, with one side larger than k and the other smaller. Finally, I considered the special case when n = 1, which is straightforward. However, during my first submission, I missed handling this particular edge case due to insufficient local testing, causing an error on the first test case. I only corrected it and achieved the correct solution on my second submission. If this similarity were anything but coincidence, I believe it would have helped me avoid errors on Problem D, where I spent a long time stuck. I submitted twice unsuccessfully and only corrected my mistake on the following day after realizing I had misunderstood the problem requirements. Had I seen or copied another user’s code, I believe I would not have struggled as much with Problem D and would have solved it correctly during the competition.
Additionally, I have local files with modification timestamps, which include my code and test cases used locally.
I sincerely hope that the officials will review my case carefully and restore my account’s integrity. Thank you very much.