### rng_58's blog

By rng_58, history, 3 years ago, ,

Hello!

We made a new programming contest website called AtCoder. I'm the admin of AtCoder.

The first international contest called AtCoder Grand Contest 001 will be held on this Saturday (Time), and we are planning to hold a lot of contests regularly. This time the problems were written by snuke. We invite you to participate in our contests!

See AtCoder's Website for detailed information.

• +644

 » 3 years ago, # |   +34 What is user ID?
•  » » 3 years ago, # ^ |   +39 Please fill both user ID and username with the same string. This corresponds to "handle" in CodeForces.
 » 3 years ago, # |   +81 The Contest time benefits asian coders a lot. :)
 » 3 years ago, # | ← Rev. 3 →   +62 Wow, I know that snuke is very strong competitive programmer!! And I look forward to seeing other writers! I guess that other writers are also strong and make good problems!
 » 3 years ago, # |   +49 Note that Japanese Standard Time is GMT+9, and there's no summer time in Japan.
 » 3 years ago, # |   +34 http://new.atcoder.jp/post/3 There are eight colors in total Let's guess which colors will be used!
•  » » 3 years ago, # ^ |   +59 I guess, purple is for admin, and from the lowest, gray, blue, green, orange, yellow, red, then black bold is for tourists.
•  » » » 3 years ago, # ^ |   +27 There should be one more color, since there are 8 colors other than admin's purple.By the way, I think there is gold for tourists!
•  » » » 3 years ago, # ^ |   +16 tourist, I guess. One and the only. :)
•  » » 3 years ago, # ^ |   +50 You don't need to guess, it's all in the code :)Interestingly, if you move green two colors up, you get the rainbow order up until brown. .username > span {font-weight:bold;} a:hover.username {text-decoration: none;} .user-red {color:#FF0000;} .user-orange {color:#FF8000;} .user-yellow {color:#C0C000;} .user-blue {color:#0000FF;} .user-cyan {color:#00C0C0;} .user-green {color:#008000;} .user-brown {color:#804000;} .user-gray {color:#808080;} .user-unrated {color:#000000;} .user-admin {color:#C000C0;} 
•  » » 3 years ago, # ^ |   +26 So it will look like this:Let's guess which color can you get if you win the first round. I guess it will be yellow.
•  » » » 3 years ago, # ^ |   +43 I thought anta was one of the top 10 in CF, but how did he change into ainta in months!?
•  » » » » 3 years ago, # ^ |   0 There are two people:ainta rank 6 and anta rank 17
•  » » » » » 3 years ago, # ^ |   0 Thank you Captain Obvious.
 » 3 years ago, # |   +174 Finally the reason why Japanese contestants don't offer problems for CF recently is revealed orz
 » 3 years ago, # | ← Rev. 2 →   +10 Wow you can request clarification pretty cool.but I have some questions first what is Affiliation ?and second after clicking on anything how do I get back to the main page I mean all I see is back to atcoder.jp which redirects me to a japanece version of the site.
•  » » 3 years ago, # ^ |   +20 Affiliation is your company or your university (or you can leave it empty). We will try to fix the second problem, thank you for pointing out.
•  » » 3 years ago, # ^ |   +10 Old Japanese version will be replaced with this new version few hours later. (It is announced by official twitter account, though in Japanese)
 » 3 years ago, # |   +19 The obligatory whitespace format is very annoying. Especially the newline in the end. (At least in Practice contest).
•  » » 3 years ago, # ^ |   +15 Do you mean the output format?In recent contests and future contests, whitespaces and newlines are not necessary in output.
•  » » » 7 months ago, # ^ | ← Rev. 2 →   +11 Hey where can I find the complete problemset on atcoder. On the homepage there are only the future and past contest. It would be good if we have all the problems stacked under one section like codeforces
 » 3 years ago, # |   0 Love that you have a coat of arms. What's the symbolism?
 » 3 years ago, # |   0 Finally, going global!! nice to hear that...
 » 3 years ago, # |   0 I couldn't find Hong Kong in the selection of country :'(
•  » » 3 years ago, # ^ |   +2 Now Hong Kong is added.
•  » » 3 years ago, # ^ | ← Rev. 2 →   -21 Because Hong Kong is not an independent country at all, it is a part of China.
•  » » » 3 years ago, # ^ |   +47 That is not for us to decide.
•  » » » 3 years ago, # ^ |   +68
•  » » » » 3 years ago, # ^ |   0
 » 3 years ago, # |   +118 What about increasing nickname length limit? :)
•  » » 3 years ago, # ^ |   +13 Now the limit is 16 characters.
•  » » » 3 years ago, # ^ | ← Rev. 2 →   +103 Do you mean he has to forget Tanya Romanova and love another girl with a shorter name so that his new handle fits in 16 characters? :D
 » 3 years ago, # |   +65 I remember there was an old contest site called AtCoder. It spams me with e-mails about contests written in Japanese since I've participated in an online mirror of APIO hosted there back in 2011 (?).
•  » » 3 years ago, # ^ |   +26 You can change it from "Settings" -> "Notification Settings".
 » 3 years ago, # |   +6 i wondered why rng_58 was not participating in recent rounds
 » 3 years ago, # |   +27 Oh, it's in English now.I've been getting e-mails about contests from AtCoder for a long time, but I can't read your runes so I didn't bother :D
 » 3 years ago, # | ← Rev. 2 →   +24 Congratulations! so many online judges nowadays ...I have heard that chinese and japanese participants are very good in math and they use math problems in their contest websites but I am always upset that I can't use them to improve my skills ( I am so weak in this kinda problems )I hope you have had some plans for improving peoples math for competitive programming in your website. It will be great for me and maybe so many others to learn how to use math and think right ...anyway thanks for your efforts ...
 » 3 years ago, # |   0 Kindly "boosting english" please!
 » 3 years ago, # |   +8 Is the user database the same as the one for the old site? I had already registered in that one and apparently I can't recover the password
•  » » » 3 years ago, # ^ |   +10 Weird, I tried that link yesterday from my phone and it didn't work, it worked today from my laptop, though. Thanks.
 » 3 years ago, # |   0 What programming languages are available?
•  » » 3 years ago, # ^ |   +13 Many available languages, so I think all you want to use is available.
•  » » 3 years ago, # ^ |   +43 Here are all: At least C++ runs fine, but I've heard some languages run extremely slow, for example Scala, Lisp, etc. You can try them on practice -> http://practice.contest.atcoder.jp/tasks/practice_1
 » 3 years ago, # |   +34 Why you guys decided to create yet another programming contest site? What will be special about this one compared to others?
•  » » 3 years ago, # ^ |   +6 There are still only a few "major" contest sites (TC, CF, and maybe Hackerrank) and they have different characteristics.
•  » » 3 years ago, # ^ |   +104 Although I'm not an employee of AtCoder, I would try to explain why AtCoder may be attractive for non-Japanese participants. rng_58, one of the legendary contestants in the world, will work as the administrator. This is great, but not all. AtCoder employs also several high-rated Japanese contestants as problem writers or testers to organize high quality contests. Because rng_58 prefers simple but mathematically interesting problems to typical and boring implementation ones, the problem set will be full of fun. If you don't know the problems written by him, say, you can view them in topcoder problem archive. AtCoder used to target only Japanese coders for several years for business reason, but now they decided to expand their work to international scale. Infrastructure is promising. AtCoder has several years history, and they have organized many contests successfully. As for now, AtCoder has organized 100 official contests, where usually 300 to 600 coders participate, and their judge server has never stopped during the contests except for their first contest. Probably this is a bit amazing even in this age. They could do such things because they have a scalable server system. Although they haven't experienced a contest with more than thousand participants, I'm currently optimistic and believe that they can run the contest safely even under severe server accesses. The target contestants in AtCoder are wide. It is from beginner to top-class coders. That's why they are going to offer several types contests according to the level of contestants. Further, as shown in above, a wide range of programming languages are supported. The contest duration and number of problems will be 100 mins/4 problems except for the first several rounds. This scale is somewhat intermediate between topcoder (75+20 mins/3 problems) and codeforces (120 mins/5 problems), which may be more balanced than others.
 » 3 years ago, # |   +10 What means "Failed to insert because of uniqueness" during signing up? Has somebody taken my username?
•  » » » 3 years ago, # ^ |   +10 OK I've done that, but the reports like "ご登録メールアドレス宛に再発行案内メールを送信しました。ご確認ください。" are not much informative for non-Japanese speakers :) Also the e-mail message was in Japanese.
•  » » » » 3 years ago, # ^ |   +18 Please check this: http://new.atcoder.jp/post/7
•  » » » » » 3 years ago, # ^ |   +18 A bugreport: I also faced up the problem "Failed to insert because of uniqueness" but the password recovery form showed me only the red message with a different text (probably an error). I spent a few iterations on trying to remember which e-mail address I could specify back then but nothing worked. Then I found an old AtCoder announcement in my inbox, carefully looked on e-mail headers and noticed that the my e-mail address was written there with an uppercase first letter. I tried to write it in that way and it worked. Even though according to a standard RFC e-mails are case-sensitive, I believe it is a good idea to force lower case before inserting an e-mail into a database since I don't know about mail servers that distinguish lower case and upper case.
 » 3 years ago, # |   +34 What do mean prefix "At" in AtCoder? :/
•  » » 3 years ago, # ^ |   +39 AtCoder is actually not a new company, but it has a history of several years. At the very initial phase of the company, it had some relationship with a Japanese IT company called AtFreaks. "At" comes from the prefix of that company. As far as I know, AtCoder has now nothing to do with AtFreaks, and "At" stands for no meanings. But I personally expect that workers in AtCoder can make up another story for "At".
•  » » » 2 years ago, # ^ | ← Rev. 2 →   +19 I've been thought that "AT" in atcoder is, the first letters of the vice president and president's surname is A and T. I was surprised that it has meaning of AtFreaks (I also didn't know such company).
•  » » 2 years ago, # ^ |   +17 Asian top Coder
 » 3 years ago, # |   +37 Wow, finally we have regular contests with 6 tasks in 100 minutes!Can we get detailed results for submissions? (like how many testcasess we passed, how many get WA, how many get TL)I remember we can see them in old AtCoder contests.
•  » » 3 years ago, # ^ |   +10 Yes.
 » 3 years ago, # |   +172 Wow, it's great to hear that new good site is coming into life! With rng_58 as admin I am sure we will be provided problems of great quality and even before first contest I have pretty big expectations :).Here is my opinion on some matters: 1) Good to see that penalty is last submission time + 5 mins * wrong submissions, I think such penalties are much better than summing times and 20 minutes for every wrong submissions (especially for short individual contests). 2) Are you sure that 6 tasks per 100 minutes is an optimal choice? I feel a bit annoyed about too short contests — sometimes TopCoder and mainly Yandex. I do not like Yandex format, because either there are too many easy problems (which are not interesting) or you get very little amount of time to fight with tougher ones. How many participants are seriously trying to solve F problem on a typical Yandex contest? 5-10? How many participants will enjoy solving it if contest is longer e.g. 150 minutes? 50? Making it last 120/150 minutes is more or less multiplying joy you are giving to contestants by 1.2/1.5 (surely it doesn't grow linearly in infinity, but as long as not many people will be able to solve all problems in given time we can make). 100 minutes is like wasting your work on purpose, I don't think contests will lose lot on competitiveness. Are there any drawbacks of making it longer? 3) I think that having colors system substantially different than already accepted by community on CF and TC will not bring any good, so I hope it more or less goes as on CF. 4) I like full feedback style :). Less randomization. However remember about preparing tests so that queue won't become too long.
•  » » 3 years ago, # ^ |   +81 Are there any drawbacks of making it longer? It's easier to find time to compete in shorter contests. So, more people are able to compete. Also, I personally prefer shorter contests because I'm better at them.
•  » » 3 years ago, # ^ |   +58 Maybe contrary to most of the people, I prefer no feedback contests, due to its randomness. Though full feedback reflects someone's skills well, randomness of no feedback makes standings unexpectable and good for regular contests for joy.
•  » » 3 years ago, # ^ |   +20 In the future we will divide it into two divisions and each division will have only four tasks (two tasks will be shared), so the contest will be 100 minutes / 4 tasks.For those who can solve E/F, A is completely trivial and B can also be solved very quickly, so I believe there's no big difference between 4 tasks and 6 tasks.
•  » » » 3 years ago, # ^ | ← Rev. 2 →   +5 What about no full feedback and the possibility of hack/challenge someone else code? Will be considered in the future? I agree that full feedback favors skilled participants but randomness makes contests funnier as hogloid said.
•  » » » » 3 years ago, # ^ |   +40 Both major sites (CF and TC) use format without instant feedback, so I guess it won't hurt to have one with it :).
•  » » » » » 3 years ago, # ^ |   -20 You don't like randomness, I got it :p. Too bad that wouldn't be possible to have something like yandex (choose to have full feedback or not) because it would carry many problems, specially with multiple accounts.
•  » » » 3 years ago, # ^ |   0 So, for a sake of convenienve let's name those problems ABCDEF and assume Div2 gets ABCD and Div1 gets CDEF. Are you aiming on a growth of difficulty so that C-F is more or less like Div1A-E on CF or rather A-F like Codeforces Div1A-E?
•  » » » » 3 years ago, # ^ |   0 C-F is intended to be similar to CF D1 A-E or SRM D1 Easy-Hard. Maybe today's round was a bit harder than intended.
 » 3 years ago, # |   +47 Finally I read and agreed to your Terms Of License.
 » 3 years ago, # |   +55 Please consider adding submission by file
•  » » 3 years ago, # ^ |   +4 also the use of "tab" in code
•  » » 3 years ago, # ^ |   -7 ctrl+A, ctrl+C, ctrl+V is faster and less susceptible to mistakes IMO.
•  » » » 3 years ago, # ^ |   +8 Not everyone codes in an environment where they feel the same way.
•  » » » » 3 years ago, # ^ |   +24 Life is hard.
•  » » » 3 years ago, # ^ | ← Rev. 3 →   +7 It's more like alttab, Carla, ctrlc, alttab, (ctrla), ctrlv. And not, it's obviously not less suspectable to mistakes
•  » » » » 3 years ago, # ^ |   +14 alttab, Carl!
•  » » » » » 3 years ago, # ^ |   0 ⌘-⇥
 » 3 years ago, # |   +30 What do you think about translating the problems from previous rounds?
•  » » 3 years ago, # ^ |   +19 It requires huge amount of time so I think we can't translate all tasks, but we may choose some of the best tasks in the archive and hold an unrated contest in the future.
 » 3 years ago, # |   0 It seems the Compilation Error detail for Visual Basic (Mono 4.2.2.30) is not available.
 » 3 years ago, # |   +20 So after the rating update, a mapping to CF (familiar) ranking+colours seems to be:[rating bottom cutoff = colour = CF colour = CF rating cutoff] 2800 = red = NutellaMaster = 2900 2400 = orange = GM/IGM = 2400 2000 = yellow = M/IM = 2200 1600 = blue = candidate master = 1900 1200 = cyan = expert = 1600 800 = green = specialist = 1400 400 = brown = pupil = 1200 nan = gray = newbie = nan The @coder cutoff drops down much faster at the lower end, I wonder if it's because the rating formula is different.
 » 3 years ago, # |   0 Two things: the filter includes AtCoder Typical Contest in addition to the three explained types (Regular, Beginner, Grand); it seems obsolete is there a way to filter by country?
 » 3 years ago, # |   0 I'd hope they change the scoring manner. Scoring of the first round has higher than some equivalent difficulty problems in TC but lower than those of CF. It's hard to guess the difficulty of problems.
 » 3 years ago, # |   0 I hope Atcoder could reduce the added value of each contest rating after the contest, as well as codeforces. Otherwise, you get more advanced color is too easy.After the first contest there are users instantly become red！ If so, I think there is not so interesting! So I suggest rng_58 and his team change this problem,rng_58 can also change the added value of rating of first contest,to be fair.
•  » » 3 years ago, # ^ |   +14 Don't worry:) rng_58, International Mathematical Olympiad gold medalist, spent much time for thinking of the rating system, so it must work well! (here is his comment about the rating system)
 » 3 years ago, # |   0 some questionshttp://new.atcoder.jp/post/1 ARC and ABC are rated?https://www.facebook.com/AtCoder Will infomation of contests be written by English on facebook?
 » 3 years ago, # |   +8 Hmm, why the (Trying/Total) of last 2 tasks are 50% in this page, while Trying are 57, 7?
•  » » 3 years ago, # ^ |   0 I think "Trying" mean "the number of users who tried this problem(during contest)" and "Total" is "TotalSubmission".
 » 3 years ago, # |   +30 Is hos.lyric involved in the project ? I haven't seen him in a while in Programming/Mathematics competitions, I really love the way he codes.
 » 3 years ago, # |   +24 Will English editorials for contest 58 (and future contests) be released? Can only find the Japanese one here