We will hold ACL Contest 1.

• Contest URL: https://atcoder.jp/contests/acl1
• Start Time: http://www.timeanddate.com/worldclock/fixedtime.html?iso=20200920T2100&p1=248
• Duration: 150 minutes
• Number of Tasks: 6
• Writer: maroonrk, yosupo, rng_58
• Tester: maroonrk, yosupo, sigma425
• Rated range: 1200 — 2799

The point values will be 300-600-600-800-900-1800.

As mentioned in this blog, you may use the library in the contest. However, it's not mandatory to install the library or learn C++; I've verified that all problems can be solved with python(pypy3).

I also tried hard to ensure the quality of the problems, and I believe that you can enjoy tasks as a usual AtCoder contest, rather than yet another practice contest. In addition to that, I would like to mention the last problem, which is unusually hard for ARC-rated contests, and we welcome >2800 coders to challenge it.

We are looking forward to your participation!

I've hacked all AC solutions of this problem, which were submitted during the contest, and I believe I can hack most of upsolving solutions. Currently, I only checked that they time out on my local machine, because "Unexpected Verdict" prevents me from uphacking. I even hacked model implementation in the editorial.

Here's my latest generator. Feel free to challenge it.

Side Note: yosupo wrote a solution, which passes the above case, but I failed it with another generator.

What I want to argue is that TL of this problem is too tight, and it affected some of the competitors. For example, I got almost the same idea as the model solution during the contest. Still, I was too scared to write it because I suspected it would time out without full optimization and possibly some tweaks like shuffling vertices/edges or contracting vertices. As I proved it myself, my thought was correct. However, this observation didn't help me, and some people who didn't think of this (or believed the weakness of the test) passed F, which seems unfair to me.

I'm not saying the round should be unrated; I think there exists a really well-optimized solution that can pass all tests. But please, problem setters and coordinators, you should give careful consideration to TL of problems. Don't set the TL by how fast your solutions run on your test. I wish future CF writes and coordinators read this, and that's the reason why I posted it as a separate blog, not a comment to the round.

P.S. Please notify me when you believe your solution can pass all tests, I'll try to challenge it.

We will hold AtCoder Grand Contest 045. This contest counts for GP30 scores.

• Contest URL: https://atcoder.jp/contests/agc045
• Start Time: http://www.timeanddate.com/worldclock/fixedtime.html?iso=20200607T2100&p1=248
• Duration: 150 minutes.
• Number of Tasks: 6
• Writer: maroonrk

• Rated range: 1200 ~

The point values will be 400-800-800-1200-1200-1800.

We are looking forward to your participation!

P.S. The AtCoder Race Ranking can be found here. I don't know who created this list, but I'd like to say thank you to them.

We will hold NOMURA Programming Competition 2020.

• Contest URL: https://atcoder.jp/contests/nomura2020
• Start Time: http://www.timeanddate.com/worldclock/fixedtime.html?iso=20200530T2100&p1=248
• Duration: 120 minutes
• Number of Tasks: 6
• Writer: kobae964, satashun, gazelle
• Rated range: ~ 2799

The point values will be 100-200-600-700-900-1000.

We are looking forward to your participation!

P.S. We are planning to set a lower bound for the rated range of AGC, so if you want to reach 2000 before the AGC next week, this contest will be a good opportunity for you.

Hello!

Opencup GP of Tokyo will be held tomorrow, with the same problems as tomorrow's MW-prefinal contest.

The writers are yosupo, sigma425, and me. I will post the editorial after the contest.

We are looking forward to your participation!

UPD The contest is over. Thank you for your participation!.

editorial

UPD2 I managed to load the contest onto the Gym. I'm sorry that the statement doesn't look pretty since it was originally written in markdown format. This is my first attempt to make a Gym contest, so there might be a mistake. If you find some problem, please let me know.

We will hold AtCoder Grand Contest 043. You may confuse this with AGC042, but it is 043. AGC042 was prepared as a mirror of WTF 2020 and we keep it as is.

This contest counts for GP30 scores.

• Contest URL: https://atcoder.jp/contests/agc043
• Start Time: http://www.timeanddate.com/worldclock/fixedtime.html?iso=20200321T2100&p1=248
• Duration: 150 minutes
• Number of Tasks: 6
• Writer: yosupo, maroonrk, sigma425
• Rated range: All

The point values will be 400-700-900-1200-1400-2100.

We are looking forward to your participation!

We will hold "Social Infrastructure Information Systems Division, Hitachi Programming Contest 2020".

• Contest URL: https://atcoder.jp/contests/hitachi2020
• Start Time: http://www.timeanddate.com/worldclock/fixedtime.html?iso=20200308T2100&p1=248
• Duration: 120 minutes
• Number of Tasks: 6
• Writer: tempura0224, heno239, beet, kort0n
• Rated range: ~ 2799

The point values will be 100 — 200 — 600 — 800 — 900 — 1100. We are looking forward to your participation!

Hello, Codeforces!

I have news today: I joined the AtCoder team and started working as an admin. It does not mean I take rng_58's place right now. I'm just a beginner as an admin, so, for the time being, we will hold contests together, and I will learn how to do it.

For this year, I don't stop participating in all AtCoder contests(especially AGCs) and aim to get a ticket for the WTF2021. I will mainly supervise ARC-level contest (and Japanese local contests).

From next year, I'll start checking submitted problems from all writers and organize contests as main admin.

Tomorrow's ARC-level contest is the first contest coordinated by me (with the help of rng_58). I'm looking forward to your participation!

The problem is now resolved. See the comment on the top.

According to the instruction sent by the ICPC WF organizer, we should upload team reference document by 25th March.

However, when I opened the WF team dashboard and clicked "Attachment", anything like uploading button didn't appear. My friend joisino said he couldn't upload his document as well. Thus I think it's a problem with the webpage, but I'm not sure.

Have you succeeded in submitting your document? Please let me know.

Hello everyone!

I have a question. Have you ever participated in a worldwide onsite contest without a US layout keyboard? I've never, but I will!

The upcoming ICPC WF 2019 provides keyboards with Portuguese layout. (source)

Ok, it can happen that US keyboards are not available. For example, in IOI 2016 in Russia, provided keyboards have a Russian layout. However, at that time, participants were able to bring their own keyboards and I was comfortably taking part in the contest.

But in the next ICPC WF, we are not allowed to do that. All we can do is to bring stickers!

I wonder why the organizers made such a decision. I think it's disastrous. Our team practiced very hard with a keyboard with US layout. I'm sure that our (and most of other teams') performance will be affected by this issue. I believe that the organizers should let us bring our own keyboards if they fail to provide US layout keyboards.

How do you think about this issue? I want to hear the community members' opinions (and, if possible, the organizers' opinions).

Thank you in advance.