phattd's blog

Introducing Arugo — A website that provides virtual rating while practicing on problemset
By phattd, 3 years ago, In English

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.

Rating progress preview
Challenge preview

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 Monarcle, rainn511, Lucario387 and many more for testing and giving helpful ideas so that I can complete my website.

Have fun training blobheart.

Edit: Thank you very much for kind words blobheart. If you want to contribute to the site, feel free to reach out to me blobheart.

Edit 2: Much thanks to emorgan for pointing out a vulnerability in the registration process. I had it patched for now.

  • Vote: I like it
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  • Vote: I do not like it

Comments Comments (105)
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3 years ago, # |
  Vote: I like it +32 Vote: I do not like it

feature request: extension for chrome to integrate with cf

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    3 years ago, # ^ |
      Vote: I like it +6 Vote: I do not like it

    I will try to make one in the future, thank you for thea idea.

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3 years ago, # |
  Vote: I like it +8 Vote: I do not like it

This is really cool , Great Work !!

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3 years ago, # |
  Vote: I like it +65 Vote: I do not like it

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://mirror.codeforces.com/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:

  1. The user enters a username and password
  2. You provide them with a problem to submit CE to
  3. You poll the Codeforces API, and once you see that they submitted the CE, you complete the registration process. If they don't submit within a reasonable time frame, you cancel the registration process. If someone else attempts to start the registration process with a username that is already currently undergoing the verification process, they get an error.
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    3 years ago, # ^ |
      Vote: I like it +4 Vote: I do not like it

    Thank you i'll fix it asap :love:

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      3 years ago, # ^ |
        Vote: I like it +29 Vote: I do not like it

      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.

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        3 years ago, # ^ |
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        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.

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3 years ago, # |
  Vote: I like it +8 Vote: I do not like it

I love the idea! Great work.

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3 years ago, # |
  Vote: I like it 0 Vote: I do not like it

khủng

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3 years ago, # |
  Vote: I like it +9 Vote: I do not like it

I've been wanting this for a while...glad it's finally out!

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3 years ago, # |
← Rev. 2   Vote: I like it +8 Vote: I do not like it

The problems are overlapping here, hiding the rating change.

Screenshot-from-2021-11-11-19-31-02

I use Google Chrome (the same thing occurs in Opera) and the zoom is at 100%.

Btw, thank you so much for this site.

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    3 years ago, # ^ |
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    I will take a look into this. Thank you for the information.

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    3 years ago, # ^ |
      Vote: I like it +13 Vote: I do not like it

    Fixed, and less visually retarded (I hope).

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3 years ago, # |
  Vote: I like it +11 Vote: I do not like it

Thank you for the awesome website!

Suggestion: the Reset Progress button should ask for confirmation

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3 years ago, # |
  Vote: I like it +2 Vote: I do not like it

loved the ingenious way of verifying cf handle via a compilation error on random problem.

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3 years ago, # |
← Rev. 3   Vote: I like it +20 Vote: I do not like it

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

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    3 years ago, # ^ |
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    Thank you for the idea. I will try to come up with a formula to it.

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3 years ago, # |
  Vote: I like it +18 Vote: I do not like 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.

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3 years ago, # |
  Vote: I like it +8 Vote: I do not like it

Great! This is really cool..

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3 years ago, # |
  Vote: I like it +18 Vote: I do not like it

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.

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    3 years ago, # ^ |
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    Thank you I will consider adding it in the future.

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3 years ago, # |
  Vote: I like it +11 Vote: I do not like it

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.

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    3 years ago, # ^ |
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    I will try to add custom time limit soon.

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3 years ago, # |
  Vote: I like it +8 Vote: I do not like it

Great Website...Finally I have motivation to solve problems besides duelling on errichto's server and doing VC on my own.

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3 years ago, # |
  Vote: I like it +8 Vote: I do not like it

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)

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    3 years ago, # ^ |
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    Sorry I will investigate into this >_<

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      3 years ago, # ^ |
        Vote: I like it +8 Vote: I do not like it

      No worries! I love the site. Also the error seems to be gone now.

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3 years ago, # |
  Vote: I like it +8 Vote: I do not like it
How to handle this????
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    3 years ago, # ^ |
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    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.

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3 years ago, # |
  Vote: I like it +8 Vote: I do not like it

Can you please add a change password option?

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    3 years ago, # ^ |
      Vote: I like it 0 Vote: I do not like it

    You can change the password in the same way you register the account. Just type along with new password.

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      3 years ago, # ^ |
        Vote: I like it +8 Vote: I do not like it

      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.

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        3 years ago, # ^ |
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        Thank you. I will try to fix this.

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3 years ago, # |
  Vote: I like it +8 Vote: I do not like it

Thank you so much!

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3 years ago, # |
  Vote: I like it 0 Vote: I do not like it

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 ?

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    3 years ago, # ^ |
    ← Rev. 2   Vote: I like it 0 Vote: I do not like 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.

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      3 years ago, # ^ |
      ← Rev. 3   Vote: I like it +5 Vote: I do not like 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.

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3 years ago, # |
  Vote: I like it +8 Vote: I do not like it

Great Website, Loving it!

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3 years ago, # |
  Vote: I like it +8 Vote: I do not like 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.

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3 years ago, # |
  Vote: I like it +9 Vote: I do not like it

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.

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3 years ago, # |
← Rev. 2   Vote: I like it 0 Vote: I do not like it

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!

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3 years ago, # |
  Vote: I like it +9 Vote: I do not like it

great website, i love the idea!

some suggestions:

  1. i'd like to have a verification after im done with a problem, e.g a message saying "you won\lost X points"

  2. 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)

  3. 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.

  4. consider adding this question to the help & about: how do you calculate the rating change of problems?

  5. the tab is called "about/help" but the title is "help&about" (im running out of good ideas :) )

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    3 years ago, # ^ |
      Vote: I like it +5 Vote: I do not like it

    Much thanks for the suggestion. I will give it an update as soon as possible.

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    3 years ago, # ^ |
      Vote: I like it +8 Vote: I do not like it

    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!

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    3 years ago, # ^ |
    ← Rev. 3   Vote: I like it +14 Vote: I do not like it

    Graph updated.

    Preview
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      3 years ago, # ^ |
        Vote: I like it +8 Vote: I do not like it

      looks good! another suggestion, i think reversing the user history would make more sense — usually the latest is on the top.

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    3 years ago, # ^ |
    ← Rev. 2   Vote: I like it +5 Vote: I do not like it

    Formula added.

    Spoiler
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      3 years ago, # ^ |
        Vote: I like it 0 Vote: I do not like it

      thank you!

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      3 years ago, # ^ |
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      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.

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        3 years ago, # ^ |
          Vote: I like it +6 Vote: I do not like it

        Yes I changed it to 16 since I think the old magnitude is a bit small.

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3 years ago, # |
  Vote: I like it +7 Vote: I do not like it

Great Work!!

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3 years ago, # |
  Vote: I like it +14 Vote: I do not like it

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.

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    3 years ago, # ^ |
      Vote: I like it +5 Vote: I do not like it

    For now, I am letting it pick random problems but prioritizing those without very few submissions.

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3 years ago, # |
  Vote: I like it +11 Vote: I do not like it

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?

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    3 years ago, # ^ |
      Vote: I like it +8 Vote: I do not like it

    Thank you for reporting, I will fix it asap.

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3 years ago, # |
  Vote: I like it +11 Vote: I do not like it

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.

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3 years ago, # |
  Vote: I like it +9 Vote: I do not like it

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

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    3 years ago, # ^ |
    ← Rev. 4   Vote: I like it +11 Vote: I do not like it

    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 :(

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      3 years ago, # ^ |
        Vote: I like it +9 Vote: I do not like it

      Let's also ping MikeMirzayanov himself if he knows anything about why the user.status API sometimes randomly returns Internal Server Error, especially with a large number of submissions. Shouldn't it be just Call limit exceeded if we've reached the quota?

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3 years ago, # |
  Vote: I like it +12 Vote: I do not like it

Another suggestion.It is required to refresh every time to see how many minutes left.Can you make the clock dynamic?

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3 years ago, # |
  Vote: I like it +5 Vote: I do not like it

One suggestion ..plz discard the "discard challenge" . that's defeats the purpose of the site

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3 years ago, # |
  Vote: I like it +16 Vote: I do not like it

The colors feel a bit off. Otherwise breathtaking!

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3 years ago, # |
  Vote: I like it +18 Vote: I do not like it

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.

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3 years ago, # |
  Vote: I like it +9 Vote: I do not like it

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.

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    3 years ago, # ^ |
      Vote: I like it 0 Vote: I do not like it

    Updated, you can now have a confirmation before accepting that challenge.

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3 years ago, # |
  Vote: I like it +9 Vote: I do not like it

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 !

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    3 years ago, # ^ |
      Vote: I like it +8 Vote: I do not like it

    phattd Are you planning to push the feature of atcoder support in near future ?

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      3 years ago, # ^ |
        Vote: I like it 0 Vote: I do not like it

      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).

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3 years ago, # |
  Vote: I like it +8 Vote: I do not like it

Thank you for the website. By the way I cannot login to the website after changing the username, hope you can fix it soon.

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    3 years ago, # ^ |
      Vote: I like it 0 Vote: I do not like it

    Thank you for reporting this. Please login with your old handle and when you login it will update your new handle automatically.

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3 years ago, # |
  Vote: I like it +8 Vote: I do not like it

When I try to register it says "No such handle authorization query been made." I didn't change my handle btw.

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3 years ago, # |
  Vote: I like it +8 Vote: I do not like it

A great project. Keeps one motivated to practice more and more questions by consistently pushing the limits.

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3 years ago, # |
  Vote: I like it +8 Vote: I do not like it

Thank you for such good tool, it's peaks problem exactly for user level, agree to previous comment, it's keeps motivated.

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3 years ago, # |
  Vote: I like it +9 Vote: I do not like it

Feature request: In user history show how much time it cost to solve problem

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3 years ago, # |
  Vote: I like it +8 Vote: I do not like it

Feature request: Add profile page that can be shared by link

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3 years ago, # |
  Vote: I like it 0 Vote: I do not like it

Today, I got this problem recommended for me: https://mirror.codeforces.com/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

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3 years ago, # |
  Vote: I like it 0 Vote: I do not like it

Couldn't open this page https://arugo.herokuapp.com/list/

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    3 years ago, # ^ |
      Vote: I like it +3 Vote: I do not like it

    Thank you for reporting. I've patched it for now.

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3 years ago, # |
  Vote: I like it 0 Vote: I do not like it

phattd Why rating loss always greater than earn rating ?

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    3 years ago, # ^ |
      Vote: I like it 0 Vote: I do not like it

    It should depends on your current rating. Infact the formula I made should have positive bias on the user.

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3 years ago, # |
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phattd is it possible to see our friend's graph?

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    3 years ago, # ^ |
      Vote: I like it 0 Vote: I do not like it

    Sorry you can only see yourself, for the sake of private training.

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      3 years ago, # ^ |
      ← Rev. 4   Vote: I like it 0 Vote: I do not like it

      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!!!

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3 years ago, # |
  Vote: I like it 0 Vote: I do not like it

The website doesn't seem to work now, I get this error when trying to open the homepage:

Error
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3 years ago, # |
  Vote: I like it 0 Vote: I do not like it

website list not working

error msg
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2 years ago, # |
← Rev. 2   Vote: I like it 0 Vote: I do not like it

Website not working. Probably stopped working ~20 days or so from now.

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2 years ago, # |
  Vote: I like it 0 Vote: I do not like it

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. !!!?

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19 months ago, # |
  Vote: I like it +19 Vote: I do not like it

Hi! Are there any plans to put it back up?

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18 months ago, # |
← Rev. 2   Vote: I like it +5 Vote: I do not like it

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.

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12 months ago, # |
  Vote: I like it +6 Vote: I do not like it

why not working now?

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