I registered for the upcoming Div3 2 days earlier, and reached expert after yesterdays Div2. Upon checking right now, it still shows me as a contestant, even though I shouldnt be. If I choose to participate as it is, will I receive any rating changes?, or is it a bug in the system?

I'm attempting to solve 894E - Ralph and Mushrooms but unfortunately getting WA on TC5, I think my approach is right, can I please get a hint as to why I might be getting a WA? Appreciated. My submission: 303151391

Yesterday, I faced a very weird issue in the question 380C - Sereja and Brackets, where my code kept on exceeding time limit. First submission: 302321365 Used 3 vectors in this to track the brackets. Fourth submission: 302322577 only modification is changing the 3 vectors into a tuple vector, still TLEs. Sixth submission: 302341164, removed the long long definition, and also commented out the overriden functions and used the original query and build directly, still exceeds the time limit. Finally, AC: 302344021 convert the tuple into a Node, and it got accepted. Can someone tell me why all submissions other than the last faced time limit exceeded even though the build and query function was the same in all of them?