Hope that I can get rating.

Wow, hope this round can be friendly to me noob :)

Plz plz give me 2 Dan I solved 4

Let me show how I solve problem C.

I stare at the screen for 30 minutes and have no idea about it. Then I write a brute force solution at first.

Then I print down each answer of 1x1, 1x2, 1x3 ... 1xn, find it is geometric progression. For 2x2, 2x3...2xn, 3x3 ... 3xn feel the same

Then I observe the ratio, wait, Fiobnacci?

Then I calculate the product, and found it is the square of product of Fiobnacci.

Finally I get AC by last moment.

how to solve B using dp? the editorial says so but doesn't give much details.

there's a mistake in C — LU / RD Marking Editorial.Assume $$$n\leq m$$$,it's not $$$(a_2a_4...a_{2n})^2a_{2n+1}^m$$$ but $$$(a_2a_4...a_{2n})^2a_{2n+1}^{m-n}$$$.

hey Guys! So I was going through the editorial of problem C and didn't understand how exactly the formula in the last step is derived. I understand how to answer for each individual component, that is the Fibonacci number, and multiply the results of each component together as they are independent. But why are we squaring the result of the multiplication of each component? and why is the term (a2n+1)^m there in the end? I enjoyed the explanation so far and really want to understand it completely. Thanks!

My rating rose to 2042 from 2028 but today I found it returned to 2028. Is my rating rolled back? I found no evidence that the contest will be unrated.