Hello Codeforces users.
Today I would like to introduce Arugo, which is a website that provides virtual rating while practicing on problemset.
On this website, you can practice problems that are suggested through a suggestion system or by your custom choice. Each problem has a window of 80 minutes to solve and if you manage to solve it in time, please validate and you will earn virtual rating. However, if you gave up early or time runs out, you will lose rating eventually. Rating progress will be displayed at the homepage through a graph like in Codeforces and through it, you can visualize your progress and stay motivated to keep going.
This site is inspired by my past training days, which I always wanted to have something like this to aid my training. Hope that it will help a lot of you who are grinding the problemset and is obsessed with the problem solved count (like me) soon reach a new level. It is my first-year project so bugs are unavoidable. If you have any trouble with it please post an issue at the GitHub I linked on the page or just comment down in the blog.
Special thanks to Lyde, rainn511, Lucario387 and many more for testing and giving helpful ideas so that I can complete my website.
Have fun training 
.
Edit: Thank you very much for kind words . If you want to contribute to the site, feel free to reach out to me .
Edit 2: Much thanks to emorgan for pointing out a vulnerability in the registration process. I had it patched for now.
feature request: extension for chrome to integrate with cf
I will try to make one in the future, thank you for thea idea.
This is really cool , Great Work !!
There might be a security vulnerability in the registration system. I noticed that the site gives you the problem you need to submit CE to before you input your username, and many people have been getting the same problem since you posted the blog: https://codeforces.net/contest/1302/status
So I could perform the following attack: continually ask the Codeforces API for all the recent CE submissions in contest 1302, and every time I see a new one, immediately register on your website with the username of the person who submitted the CE, and a password only I know. Then while I was running my script, nobody would be able to register on your site, and anyone who attempted to do so would be permanently locked out of using their username, since I now own their account on your site.
To do it securely, you could do something like this:
Thank you i'll fix it asap :love:
Also, you should make sure that when you poll for the recent CE submission, you check that the submission time is after the registration process was started -- otherwise, I could attack it like this: suppose some user has gotten CE on problem X in the past, then I repeatedly attempt to register with that person's username and allow the timer to expire, until I get X as the one I am supposed to submit to. Then I would automatically pass and take that person's username.
Yup, I will surely try to fix it. Probably just allow one verification per validation query so no one can reuse a submission. :blove: Much thanks for your comment.
I love the idea! Great work.
khủng
I've been wanting this for a while...glad it's finally out!
The problems are overlapping here, hiding the rating change.
I use Google Chrome (the same thing occurs in Opera) and the zoom is at 100%.
Btw, thank you so much for this site.
I will take a look into this. Thank you for the information.
Fixed, and less visually retarded (I hope).
It's ok now, thanks for fixing this.
Thank you for the awesome website!
Suggestion: the Reset Progress button should ask for confirmation
Thank you, I'll be on it.
Confirmation added.
loved the ingenious way of verifying cf handle via a compilation error on random problem.
greatest codeforces related website till date
I have a suggestion.If someone solves faster than 80 minutes and with less wrong submissions he/she will get more points
Thank you for the idea. I will try to come up with a formula to it.
Amazing tool! I finally have the motivation to solve random problems now.
One suggestion is adding a "Congratulations on solving" or "Accepted" in green text after we solve a problem. It feels good to see that.
Thank you I will try to add it.
Edit: Added.
Great! This is really cool..
Thanks for this incredible tool! A request from my side would be to add a "User History" page with the list of problems solved + time taken.
Thank you I will consider adding it in the future.
I was looking for something like that to come. Thanks, mate.
Request: Can you please add a customizable time limit. I think for many problems 80 minutes is too much.
I will try to add custom time limit soon.
Great Website...Finally I have motivation to solve problems besides duelling on errichto's server and doing VC on my own.
Not sure if this is a known error, but right now when I click on challenge I get shown this: I'm not a web developer so I have no clue what this means! Hopefully you might understand it. (https://i.ibb.co/Vq4P3cr/Screen-Shot-2021-11-12-at-8-54-30-AM.png)
Sorry I will investigate into this >_<
No worries! I love the site. Also the error seems to be gone now.
This handle has not submitted a compile error to 1302I recently.
You can submit a compile error to that problem, and also make sure that it is the last submission to codeforces by the time you register. I am trying to change the registration to a more secured way but for now that is how to register.
Can you please add a change password option?
You can change the password in the same way you register the account. Just type along with new password.
Ok thanks. Just one more thing. When I open arugo on phone the top left three mark button isn't responding. So you might wanna check it out. Btw great work.
Thank you. I will try to fix this.
Thank you so much!
I have patched (maybe ?) the registration process with random problem and once validation per query. The time limit should be 2 minutes until it expires. Much thanks to emorgan for pointing this out. Maybe can you guys give it a little test to it ?
By the way I just saw a commit stating that you didn't encrypt passwords.... If I registered before that update, can I rest assured my password is safe now xD or should I reregister to update it.
It was my mistake :( glad I found out in time. Sure you can register now. Actually maybe only 5 6 users were affected but if they query another change then it should begone.
Great Website, Loving it!
Thank you so much for this amazing website. Godspeed to you! I had a feature request: Can you please add a "user history" of solved problems? And beside each solved problem, can we see the rating of that problem? It would be nice if we could sort our solved problems by their rating. In that way, we can keep count of how many problems we solved from each level.
Thank you. User history added.
Suggestion — You can only see the rating change for the recommended problems. However, if you search for a problem, it just starts the timer. Could you add a feature where you can see the rating change and then validate? I understand if this is unnecessary because it could discourage people from solving problems if they don't want to lose rating.
Just got this error after writing a contest. I get this beauty every time I click on the "list" button. Not sure if it's related to writing the contest, but I mentioned it just in case, to make it easier for you to catch the error and figure out what's wrong.
Anyway, thanks a lot for your awesome website!
sorry I will take a look at it
great website, i love the idea!
some suggestions:
i'd like to have a verification after im done with a problem, e.g a message saying "you won\lost X points"
consider adding vertices in the graph to separate problems — in your graph there's a continuous segment between problem 16 and problem 19. (like the codeforces rating graph)
in the user history, when clicking on the delta button of problems, it scrolls the page to the graph, it would be nice if it could also highlight the relevant part of the graph. or, the vertices of the graph (idea #2) would be links to the problems.
consider adding this question to the help & about: how do you calculate the rating change of problems?
the tab is called "about/help" but the title is "help&about" (im running out of good ideas :) )
Much thanks for the suggestion. I will give it an update as soon as possible.
Being able to hover over graph vertices would be also really nice, I didn't realize that I used it so often on Codeforces. So I definitely suggest improving graphs to be your first priority. Thanks for such a cool website!
Graph updated.
looks good! another suggestion, i think reversing the user history would make more sense — usually the latest is on the top.
Fixed.
thank you!
Formula added.
thank you!
and what about the magnitude? is it getting bigger when you solve a lot of problems in a row? i think mine is currently about 15.
Yes I changed it to 16 since I think the old magnitude is a bit small.
Great Work!!
How are the problems suggested? Is there any particular way or they are just random tasks with near ratings? Anyway, thanks it seems as a helpful tool <3.
For now, I am letting it pick random problems but prioritizing those without very few submissions.
I've started challenge, but got AC only after about 2 hours from timer was started. After that I've clicked 'validation' button — I thought that it would check real duration, so my rating would decrease. But my rating increased: i think it is because i haven't reload page and timer on the page showed 5 minutes to the end.
Is it bug or feature?
Thank you for reporting, I will fix it asap.
This website is great. Please add the option to customize the time limit so that a person can set the time limit lesser than 80 minutes if they want.
I'm about to lose rating because CF API is not working. This is like the 4th website built on the CF API that I'm breaking because of my huge submission count.
pls help
I will try to come up with a cache solution for this >_<
Edit: I temporarily added an option to discard the problem, perhaps will work during the down time of the API :(
Let's also ping MikeMirzayanov himself if he knows anything about why the
user.statusAPI sometimes randomly returnsInternal Server Error, especially with a large number of submissions. Shouldn't it be justCall limit exceededif we've reached the quota?Another suggestion.It is required to refresh every time to see how many minutes left.Can you make the clock dynamic?
Solved thanks to ssvb.
I'm not a web developer, but isn't it basically just something as simple as adding something like https://www.w3schools.com/howto/howto_js_countdown.asp to https://github.com/polarity-cf/arugo/blob/main/templates/challenge.html
Thank you for your help, I think I overlooked it and got it solved now.
thanks ssvb and phattd
One suggestion ..plz discard the "discard challenge" . that's defeats the purpose of the site
The colors feel a bit off. Otherwise breathtaking!
Today the site suggested a problem that was already solved by me. I don't know if the repeat was intentional. Also, my previous submission was in div2 contest but the suggested problem was from div1 -> this might be the problem if repeat was not intentional.
Suggestion: the Manual Challenge Choice should show the problem found and ask for confirmation. Sometimes I may enter a wrong problem ID that I don’t want.
Updated, you can now have a confirmation before accepting that challenge.
really thank you for this website, I have become addicted to it, I hope that you will add Atcoder support as well in future :), doomo arigato !
phattd Are you planning to push the feature of atcoder support in near future ?
I am afraid that it won't be in the near future, but I will give it a try one day. For the time being, practicing on kenkoooo is still great I believe (even if I'm building one for atcoder, I will probably have to use kenkoooo's unofficial API too).
Thank you for the website. By the way I cannot login to the website after changing the username, hope you can fix it soon.
Thank you for reporting this. Please login with your old handle and when you login it will update your new handle automatically.
When I try to register it says "No such handle authorization query been made." I didn't change my handle btw.
Thank you for letting me know, I've fixed it
Unfortunately I still have the same issue.
A great project. Keeps one motivated to practice more and more questions by consistently pushing the limits.
Thank you for such good tool, it's peaks problem exactly for user level, agree to previous comment, it's keeps motivated.
Feature request: In user history show how much time it cost to solve problem
Feature request: Add profile page that can be shared by link
Today, I got this problem recommended for me: https://codeforces.net/contest/1002/problem/A3
Since its title was very strange, I fortunately peeked at it before accepting the challenge. I think it would be good to avoid that problems like this get recommended (or add some warning if they do), so people do not lose rating after starting the challenge for a quantum computing problem.
Thanks for the very useful tool btw
Couldn't open this page https://arugo.herokuapp.com/list/
Thank you for reporting. I've patched it for now.
phattd Why rating loss always greater than earn rating ?
It should depends on your current rating. Infact the formula I made should have positive bias on the user.
phattd is it possible to see our friend's graph?
Sorry you can only see yourself, for the sake of private training.
can you make the problem suggestion to only those problems that have an editorial because not having an editorial of a problem after exhausting every idea that I can get is frustrating as I won't know what am I missing to solve that problem! Also if you'd like, you can add a feature to see our rating in the graph on the point our cursor is. just thought it would look cooler!!!
The website doesn't seem to work now, I get this error when trying to open the homepage:
Application error
An error occurred in the application and your page could not be served. If you are the application owner, check your logs for details. You can do this from the Heroku CLI with the command
heroku logs --tailwebsite list not working
IndexError at /list/ list index out of range Request Method: GET Request URL: https://arugo.herokuapp.com/list/ Django Version: 3.2.9 Exception Type: IndexError Exception Value: list index out of range Exception Location: /app/.heroku/python/lib/python3.8/site-packages/django/db/models/query.py, line 318, in getitem Python Executable: /app/.heroku/python/bin/python Python Version: 3.8.6 Python Path: ['/app/.heroku/python/bin', '/app', '/app/.heroku/python/lib/python38.zip', '/app/.heroku/python/lib/python3.8', '/app/.heroku/python/lib/python3.8/lib-dynload', '/app/.heroku/python/lib/python3.8/site-packages'] Server time: Thu, 31 Mar 2022 19:21:03 +0000
Website not working. Probably stopped working ~20 days or so from now.
I guess, the reason is the same as mentioned in https://codeforces.net/blog/entry/109469 (herokuapp.com are closing their free accounts on Nov 28th).
phattd can you provide the GitHub link to your site(Arugo) so that Arugo lovers can still enjoy it locally. As Heroku has stopped providing free services. !!!?
Hi! Are there any plans to put it back up?
Oh, Arugo, a platform of grace,
Where competitive coding finds its place.
I pen this humble plea to you,
To bring back the magic that I once knew.
In the realm of bits and code,
Arugo's embrace, my skills bestowed.
With each challenge, a new height I'd climb,
My mind honed sharp, in rhythm and rhyme.
From algorithms intricate and wide,
To data structures I'd confide,
Arugo, you've been my guiding light,
Through countless lines of code I'd write.
Oh, Arugo, the knowledge you impart,
Has shaped my mind, my coding heart.
In practice rounds and contests grand,
I found my place, a thriving band.
So, I beseech you, Arugo dear,
Bring back the platform we hold near.
Let others taste the joy I've known,
In the realm of coding, their skills be honed.
For Arugo, you've been my loyal guide,
In this vast coding world, by my side.
Revive the platform, let it thrive,
Where coders dare to dream and strive.
Arugo, I thank you, with utmost glee,
For the invaluable growth you've given me.
May your presence endure and never lack,
A sanctuary for coders to come back.
why not working now?