Since I was not able to find an announcement for ARC99 , maybe we can discuss some problems here?!

I wanted to ask about the problem D of ARC99, how did you solve it? The editorial way is incomplete .. I was trying to find some pattern in snuke's numbers but was not able to find any!..

I had a somewhat out of topic but still kind of related question. How do you add friends in atcoder and is there any way to see friends standings there?

I use https://beta.atcoder.jp version of the site, and there in the standings, there are two options:

1) "Show fav button" to add favorites/friends by clicking on a star beside their username

2) "Show favs only" to show friend-only standings

My solution for D.

1. We always increase a digit in the number but never decrease.

2. we only care about lowest non 9 digit in the number.Because on increasing that if condition holds,it always holds.

3. Using 2, we get that other than highest 3(or maybe 2) digits, rest all must be 9.

4. Now we can iterate over number of digits and first 3 positions and find all numbers.

5. 15*9*9*9*(checking time) algo is here.

My doubts.

Why is system so slow??

I see that I ranked below 100 after my first got evaluated and just before it got evaluated I was above 400. My belief was it was a submission queue. Isnt it a queue(please dont say its a stack).

Uploaded full editorial.