[contest:1048] was decided to be unrated because of a major issue in Div.2 D / Div.1 B. The statement missed an important condition (operation 2 can only be performed once), which resulted in the solution being incorrect on the following countercase.

1
3 1
3 4 1 2
1 4

Because of this, several top participants were unable to solve the problem, which was why we decided to make the round unrated.

The problem was originally used as a B, which only had a single query, and at that point, the statement and brute force were both correct. When we decided to change it to a D, I thought that the solution is the same without the condition of "operation 2 can only be performed once", so I removed it to make the statement cleaner. The brute force solution for D was a $$$O(n^3)$$$ check for $$$a_i \gt a_j \gt a_k$$$ since we already tested that in B, but did not realise that the condition might have changed after removing the condition. Hence, we did not manage to catch the mistake when stress testing the modified D.

I admit that this is fully my fault, and I take full responsibility for this issue. I hope that the announcement blog for round 1048 will stop being downvoted, and all of you are free to downvote my blog instead. The authors worked very hard on this round, and it was fully my fault for suggesting the wrong change, and not checking the new brute force and stress tests properly before the round was scheduled. I am very sorry for disappointing everyone, and I will be more careful in the future to ensure that this does not happen again.