Updating submission 4 times in a row resulting short temporary ban and it's so annoying. Can you make anti-ddos more weaker? Maybe do it more tolerant toward "trusted" users, where trusted can be defined as you like: big rating, old account, big contrib, idk. Pls do something...

Im working on this problem: Given $$$n$$$ and $$$c$$$, How many sequences $$$A$$$ of length $$$n$$$ satisfy the following conditions:

• $$$1\leq a_{i} \leq c$$$
• $$$\forall i \in {1,2,\ldots,n-1}: a_{i} | a_{i+1} $$$ ($$$a_{i+1}$$$ is multiple of $$$a_{i}$$$)

I found really cool fact:

• lets $$$ANS_{n,c}$$$ be the answer for $$$n$$$, $$$c$$$

• Lets $$$A_{c} = ANS_{1,c},ANS_{2,c},ANS_{3,c},\ldots$$$

Surprisingly, $$$A_{c}$$$ can be represented as polynomial $$$P_{c}$$$ of degree exactly $$$\lfloor{\log_2{c}}\rfloor$$$, so $$$P_{c}(X) = ANS_{X,c}$$$

Why is even $$$\log_2$$$ came up here?

By the way, im struggle to find pattern for coefficients of $$$P_{c}$$$. I noticed that (Lets coefficient of $$$x^i$$$ be $$$P_{c_{i}}$$$ ) $$$P_{c_{i}} = \frac{F(c,i)}{(\lfloor{\log_2{c}}\rfloor + i)!}$$$ where $$${F(c,i)}$$$ is some weird function I cannot determine.

I attached calculated coefficients and code for calculating them, hope someone will see a pattern there.

If someone have any information about it, please provide!

link to atcoder problem and my solution which uses the fact about polynomial of degree $$$\lfloor{\log_2{c}}\rfloor$$$

I feel really disappointed after todays Codeforces Round 741 (Div. 2) because of very strong samples in 1562D1 - Two Hundred Twenty One (easy version).

• the fact that answer is always <= 2 is not so obvious, but samples made it clear.

• samples also made it clear that answer is depends on parity of the sign-variable sum

I know a lot of people (including myself) who did not prove it at all. I think problem solving is not about just getting Accepted by staring at samples, but analysing problem and come up with ideas. I spent more time analysing problem A and I don't think it is right