Всем привет! Я на прошлом контесте предлагал всем желающий потестировать мой сервис предсказания изменений рейтинга. Сейчас я рад представить его!
Огромное количество Ваших нервных клеток погибает, так и не дождавшись обновления рейтинга. Хватит это терпеть! Теперь Вы можете использовать данный сервис для приблизительно вычисления изменения рейтинга.
Наиболее интересная составляющая — расширение для хрома. Оно изменять страницу положения, добавляя предсказываемые дельты. Расширения доступны для 3х браузеров:
Расширение в работе: 
Более детальную информацию (seed, rank, expected delta, etc.) можно посмотреть на сайте. 
Проект до сих пор в бете, так что предсказания не очень точны. В среднем ошибка не превышает 5 очков, но для участников из конца положения ошибка может достигать нескольки сотен.
Я хочу выразить благодарность Rubanenko и всей команде разработчиков NBHEXT за их открытые исходники и MikeMirzayanov за отличную платформу Codeforces с публичным API и формулами подсчета рейтинга!
AWESOME UPD Предсказание для сегоднешнего контеста (cf #399) полностью соответствует реальным изменениям! Спасибо riadwaw! Он направил меня в правильное русло, и баг рассчета рейтинга пофикшен!
Maybe I miss something but why use this, when there is NBHEXT? Did you overcome some of its bugs? Please, give more information on how this differs from NBHEXT :)
NBHEXT not working
My bad, I didn't know :)
NBHEXT predicts rating changes using your browser (did you notice that your browser works slowly and is lagging while doing predictions?) CF-Predictor extension get prediction from own server, so all calculation are made on serverside. And yes, NBHEXT is not working now :(
Now I see, thanks :)
Not for Mozilla? Please make it for Mozilla too.
It is on validation now. I hope, it doesn't take lot of time:)
deleted.
You know, browser extensions work that way that you can enable and disable them whenever you want.
Yeah, my bad.
Funny, on attached screen all but one prediciton were good with tolerance of two points, but tourist's prediciton was way off (by 46 points). Probably there is a bug that comes to light only when we are dealing with very high rated users. Maybe you did same bug as original bug thanks to which tourist once exceeded 4000 points :)?
Maybe I did not understand bug correctly, but wasn't the rating change caused by tourist beating himself? If it's the same bug, wouldn't the prediction show him as losing more rating, because he lost to himself instead?
Nope. You only get the probability of him beating himself, no matter what places the others take. http://mirror.codeforces.com/blog/entry/44214
Please make it for Mozilla too.****
I'm afraid it doesn't happen soon.
It seems the variance of the tool is quite high. Last contest I got an expected change of +22 (which seemed way off) and the real change was -63. I also saw people with similar results and similar starting rating getting a negative expected rating change.
This was prediction before system tests. It caused because server gets to many request and have no time to calculate new rating prediction. I will fix this prior next round.
If you a curious about prediction after system tests you could see it at static page here.
It predicts to you -65, 2 point lower than actual results.
sorry for my bugs
What about showing the last update time of the prediction so that people can know more about it, and also how the prediction should be considered as accurate.
For instance, from the last update time shown, people can know if the prediction is about middle of the contest, end of contest but before systest, or after systest. So it is much more clear.
I hope you can consider adding something like this. Thanks for such a great tool anyway:)
Auto comment: topic has been updated by WasylF (previous revision, new revision, compare).
Apparently, the rating site is down (at least for me). Any ideas why?
The site is up now. But when I try to select a contest and click "Get rating prediction", the results won't display at all. The browser seems to load infinitely instead.
Site is again down now. :|
I think I found a bug. See this —
He is in my starred user list, He submitted A and got WA on pretest 1 [skipped]. But will this even happen? He will get near +77? o.O
Yeah, you are right this is bug. mdshs.shanto has a quite low rating (887) and my program calculated his seed as 2922. He took place much higher, so his rating should increase. But official cf rating works somehow different, and I don't know where my mistake((
Maybe in case of several people on the same place from A to B, you consider their rank to be A, while it's probably considered as (A + B)/ 2;
I will check this, but in the official shared code rank calculates as in standings:
If all people get same number of points, this code will return contestants.size() as far as I understand the code. In standings everybody would be first
Excellent Work! Forked it as Well :)
Your tool was perfectly worked yesterday! Thanks man!
I suggest to add a Disable/Enable button for the extension as sometimes i wanna to hide it during the contest
Похоже, что сервис упал:(
UPD: заработало
Че-то в последнем контесте (428) вообще все полностью неправильно предсказалось, хотя на предыдущем было идеально.
Такое впечатление, что загружается неправильно рейтинг участников — у соседних в турнирной сетке отображается ровно одинаковое изменение рейтинга при огромной их разнице в исходном рейтинге. Например, вот два чувака вокруг меня в турнирной сетке с практически равными результатами, у одного рейтинг 1376, ему написало +41, хотя по факту +64, у другого 1716, ему написало тоже +41, хотя по факту -31.
Браузер Chrome последний
К сожалению я был далеко от нормального интернета и не смог вовремя проверить. Возможно действительно загрузился рейтинг с предыдущего контеста. Со следующим раундом (429) все должно быть впорядке.
В раунде 429 в таблице везде стоят нули.
Site is down.I am unable to open it
Shows 0 to me ?
Yept, maybe because of some problems on the server. Lets hope it will be fixed as soon as possible :)
*ept
It's still not working!!!
CF-Predictor seems to be working now but rating change for #431 Div.2 is wrong. Why?
Can sombody help me set this extension up...I added it to chrome extentions...but dont know how it works
You should just open standings page of active or recently ended contest. You will see a rating change in the last column.
For example: last contest here
PS Probably you have a slow internet connection, in this case downloading data could take a while.
Thats an amazing extension...Almost accurate it showed +20 and I got +21...You did an amazing job
I think the web interface is really ugly now...
UPD: Great interface now.
I'm sorry, I'm 100% noob in the frontend. Do you have any better proposal for start page design?
Just use plain text, no fonts, no styles.
Auto comment: topic has been updated by WasylF (previous revision, new revision, compare).
Please predict the Good Bye 2017 round's ratings, taking into account the changed ratings due to the last Educational round.
Cf-Predictor неправильно работает с пользователями, изменившими в новом году свой хэндл. Например, пользователь TheWayISteppedOutTheCar на сайте указан под своим предыдущим хэндлом "subird". Рейтинг subird на сайте cf-predictor равен последнему рейтингу TheWayISteppedOutTheCar под ником subird на Codeforces; в плагине для браузера предсказание рейтинга для TheWayISteppedOutTheCar не работает вовсе.
WasylF предиктор не работает для тех кто менял хэндл
опа теперь работает
скорее всего работает для тех, кто уже написал хотя бы один раунд под новым логином. Спасибо за информацию, попробую исправить.
Please update it to the new rating system.
I think they have updated it for Div.2 and Div.3 according to the new rating system, but forgot educational rounds :(
Isn't it the first educational round since new rating was introduced?
Hi! Could you please tell more specific, what doesn't work?
In educational rounds rating changes for purple users aren't shown.
Thanks! I didn't notice this change:)
UPD: Fixed
Sorry for the late answer, thanks to you too :)
WasylF, it seems that the extension doesn't work for HTTPS version of Codeforces. Please fix.
Thank you! Updated for Chrome & FireFox! There is some issues with opera. I don't know how soon it be solved.
Thanks for the fast update, it works now. Tested on Firefox 60.
WasylF, It's still not working on my chrome for HTTPS version :(
skmonir, could you please check version of extension? It should be 1.2.3
WasylF, yes. It's 1.2.3. In fact, when it wasn't working, I removed it and added again from the chrome web store. So it's latest version.
You are right. But we can visited this url to find our rating changes.
It can't work now.
Do not worry, everything is fine :) I'll turn it on before the next contest. Free heroku account gives you a limited amount of free hours per month, so I need to spend them wisely :)
Have you considered Azure Web Services? Don't know if it would work for you, they offer a 1 year free license for students, with a variety of services
What about Microsoft Edge user???
Hello!
I'm a Microsoft Edge user, too. I use tampermonkey to install CF-Predictor on my computer.
You can install tampermonkey here -> https://tampermonkey.net/
And then install CF-Predictor here -> https://greasyfork.org/zh-CN/scripts/38050-cf-predictor
I hope it will help you.
Auto comment: topic has been updated by WasylF (previous revision, new revision, compare).
Why not for safari...???
In case the post is too long and it's hard to find links, this is a summary:
The predictor was working fine till yesterday. However, today I updated my Firefox web browser and it's not working anymore. I am running Firefox Quantum (64.0) in Ubuntu 18.04.
no, that's just because the server for cf predictor crashed
Phew... I thought the newer version is not supported and so I have to reinstall the outdated one.
Got Safari and want to stick with it....
Extensions, get you out of "tension".
WasylF has the CF rating system is being changed.In last contest predictor showed -7 rating change.But it was actually -23
Something similar happened to me too.
WasylF CF-Predictor hasn't been working for me lately(it doesn't display the delta column)
I'm using Google Chrome and I tried uninstalling and installing it back, but still no success.
I have the same problem with chrome. I have downloaded the Mozila Firefox, where the predictor works.
yeah, me too!
I guess we'll have to go back to the tried-and-true method of "Look at your rank and guess the expected delta and then pray you get high rating"
I like your approach! suffering is madatory party of competitive programming :D But if you like, website with predictions still works.
Thank you for reporting, I'll look on this.
UPD I've found the reason of issue. In last chrome update they changed Cross-Origin Read Blocking policy. And the actual problem is that I can't update code ASAP. I recently started working in Google and they have pretty strict policy about open source projects. I'll try to come up with some solution, but sorry, no promises.
Current solution is to use website.
Hi WasylF, I have fixed the CF-Predictor Chrome extensions and it is working on Chrome 73. I am sending you a PR, please review it and if possible update the Extension as soon as possible.
UDP1
YOU SHOULD REALLY WAIT FOR OFFICIAL RELEASE
For those who want to test it now, Download this, Uninstall the old version as they are signed with different keys. Follow this tutorial on how to manually install chrome extensions. (It's easy).
UDP2
To install official extension again, you must remove this
UDP3
The new extension is available in the chrome store. Update now
Thank you a lot! Extension has been updated (version 1.2.4) and now it works fine!
The add-on used to work on Firefox Android but now I can't even download it!
Update your Firefox. It worked for me.
Thanks. I looked it up and found the solution months ago.
Excuse me,can anyone tell me the exact rating calculation formula?
I have a suggestion to improve CF predictor. First of all thank you for the amazing extenion.
Feature: Add rating change for virtual contest. you could color the rating with red or any color to show that it is virtual
In the recent contest Codeforces Global Round 5, the rating prediction is wrong for a user with negative rating. (predicted -48, real -4)
Possible reason: the binary search algorithm (
getRatingToRankfunction) in the official code initialize theleftvariable to 1, so the result is incorrect for values < 1.Mike pls fix
I'm having some problems in the extension, its not working in Opera but works in Chrome. Can someone help me more with opera?
It was not working for me too. I installed an extension that helps to download Chrome's extensions, here is the link https://addons.opera.com/en/extensions/details/install-chrome-extensions/
then you can download Chrome's predictor and it will work perfectly.
thanks, I tried to open chrome web store,from Opera browser, and from the extentions I downloaded the CF-predictor and it worked.
I think that something is broken :(
Yes, for some users, it takes 1500 rating as previous rating. Seen here:
https://cf-predictor-frontend.herokuapp.com/roundResults.jsp?contestName=Codeforces+Round+%23618+%28Div.+1%29&contestId=1299&sbm=Get+rating+prediction
Yeah, it happened because of New Year magic with the possibility to rename accounts. It should be fixed by now.
It doesnt work in virtual participant. Can you help me ?
Sorry, but it doesn't suppose to work for virtual contests because it would generate additional load on the server.
Ok
Can you please make it do client side calculations for that one, a lot of people would really appreciate it!
Thanks ahead :D
How is it possible that this post isn't +1000?
I've edited the JS File a bit so that it works in Safari ( macOS Catalina ). See the full details here
I did all steps that are mentioned there, but I'm not able to see rating changes prediction in a past contest in Safari.
Isn't there a button like in other web browsers?
Sorry but can it predict at the moment we chose ?
What happen to me ;-; It doesnt show anymore ;-;
i suppose all profiles are temporary blocked and cfpr needs ratings to work?
Oh, maybe it is. I use this a lot and get confused when it doesnt work haha ~~
Your rating change is a function of the ratings of the participants in the contest you did. It follows that the predictor needs ratings to operate, which, among other cf features were not present during the contest.
It showed -48 for me and -62 for my friend but we both got -16
Hey, the rating predictor isn't predicting correct delta. Can you please fix it. Thanks.
Can anyone please explain how the seed of a coder is calculated?
Pretty sure the seed is the rank of the competitor before the contest compared to the other competitors. So the top rated participant gets seed 1, second most rated gets seed 2, etc.
BUG: Rating predictions for today's contest were based on the ratings before yesterday's contest so they are inaccurate.
How to add this extension for Micorsoft Edge?
As far as I know new chromium based microsoft edge supports chrome extensions. U can add it by clicking on chrome extension of it.
Similar to this issue, deltas today were calculated using ratings from 2 contests ago.
CF-predictor is down now and the addon is not working. Is there any alternative?
UPD it seems, there were some problems with Heroku. Works now.
CF-predictor is down again, any idea why?
UPD: It's back up!
It's working as of now .
The site is up now, but the extension is not working.
extension is not working now
From what I have observed in past 2-3 contest, it doesn't work during the 12-hour hacking phase.
Is it just me or is the extension not working?
Its not working bro.
It predicts wrong delta for those who have changed their handle using magic . My handle was previously taken by someone who had not participated. CF predictor is calculating delta using that rating. WasylF Please look into this.
I used safari-web-extension-converter to let it and competitive companion run on Safari(>14.0),It is now available on the AppStore,but unfortunately,According to CORS I cannot send the request to CF-Predictor ,so you need to disable Cross-Origin Restrictions before use.
After I updated my username, it is not predicting my rating change
I have been using your tool for a long time. In Codeforces Round 799 (Div. 4) contest held yesterday, the tool showed an expected +17 points rating-change by the end of the system test. Nonetheless, the actual rating-change made by the CF system was -8 points!
What would be a plausible reason for this large inaccuracy in predicting the rate change?
Is it possible to update the tool so as to make it more accurate?
P.S. I have not updated my CF username since joining the site.
Maybe, you should add an auto-update feature, which automatically updates the delta when the real rating changes occur.
The CF-predictor is not working, please help if anyone knows any other tool/extension to predict rating changes
Neither this nor Carrot is working at the moment because the Codeforces API is down, once that issue is fixed my guess is that both extensions will go back to working just fine.
Great Extension! And thank you WasylF!
Is it possible to share the source please...
Refer to this comment
Why I've download the extension but it doesn't
this stopped working long ago. try this instead.
This doesn't seems to be working, neither does carrot. Is there any other tool to compute individual elo performance?