ahmed_aly's blog

By ahmed_aly, history, 3 months ago, In English,

I'm sadly announcing that a2oj.com (A2 Online Judge) will be retiring by end of 2019, I'll shut it down at midnight on New Year's Eve. It was something I took care of for about 10 years.

I'm really sorry, but I prefer not to explain my reasons, so please don't ask me why I'm doing this, it was hard enough for me to make this decision, and also please don't try to convince me to change my mind.

I'd like to say thank you to everyone who used it, and please accept my sincere apologies for shutting it down.

If you have something good to say about A2OJ (how you used it or how it helped you in any way), I'd love to read that, please send it to the following email (or in a comment here): bye@a2oj.com

Also please feel free to take a copy of any data you can access, and if you need some data in a specific format, please send your request to the following email: bye@a2oj.com (if the data isn't public, make sure to send from your registered and verified email which can access this data). I'll do my best to fulfill all requests.

Please only use the above email, because soon I'll be deactivating my personal Facebook account again, I'll also deactivate A2 Online Judge.

Edit 1: I'll keep a static version of all Ladders & Categories.

Edit 2: Here's how I generated the ladders, in case if anyone wants to implement it: https://codeforces.com/blog/entry/47442

Edit 3: A2 Online Judge is shut down now, and a static version of all ladders and categories is available. And here are some final numbers for the record:

Database numbers:

  • 24,012,628 total number of database rows.
  • 99,242 registered users.
  • 33,133 created contests.
  • 1,581,430 submissions collected from other online judges.
  • 937,658 different source codes stored in the database.
  • 261,733 compiled and executed source codes (in 54 different languages).
  • 6,144,545 user solved problem entries (detected that a user solved a problem).
  • 377,580 problems added to contests.

Google Analytics numbers:

  • 30,265,387 page views.
  • 5,252,045 sessions.
  • 1,157,668 users.

Top 10 countries from Google Analytics:

  1. India
  2. Egypt
  3. Brazil
  4. United States
  5. Bangladesh
  6. Peru
  7. Jordan
  8. Syria
  9. Colombia
  10. Bolivia
 
 
 
 
  • Vote: I like it
  • +1793
  • Vote: I do not like it

»
3 months ago, # |
  Vote: I like it +26 Vote: I do not like it

I just started using it and sadly its retiring already. But, thanks for your 10+ years of work for newbies like me.

»
3 months ago, # |
Rev. 2   Vote: I like it +9 Vote: I do not like it

is there any other sites as such which can help us like a2 online judge ahmed_aly?

and thanks for the site. I had recently started using it again

»
3 months ago, # |
  Vote: I like it +15 Vote: I do not like it

It's so sad to know that you will be closing the site. Good luck for your future.

Can anyone please make a Google sheet for all the ladders that are present on A2OJ.

Thanks in Advance.

  • »
    »
    3 months ago, # ^ |
      Vote: I like it +78 Vote: I do not like it

    I'll keep static pages of all Ladders & Categories.

    • »
      »
      »
      3 months ago, # ^ |
        Vote: I like it +7 Vote: I do not like it

      means there will be no updates in the website but the problems will be there

      • »
        »
        »
        »
        3 months ago, # ^ |
          Vote: I like it 0 Vote: I do not like it

        Does that mean I can access those ladder, feature of problem dependency will be there or not?

    • »
      »
      »
      3 months ago, # ^ |
      Rev. 5   Vote: I like it +160 Vote: I do not like it

      Instead of a static version of ladders. How about creating a cf group named "A2OJ" and adding all ladders under contest "Ladder Name: 20 — 2100 <= Codeforces Rating <= 2199 (by ahmed_aly)"
      It can at least replicate a similar experience and much more useful than static version.
      I̶ ̶c̶a̶n̶ ̶c̶r̶e̶a̶t̶e̶ ̶a̶ ̶g̶r̶o̶u̶p̶ ̶a̶n̶d̶ ̶p̶r̶o̶v̶i̶d̶e̶ ̶w̶i̶t̶h̶ ̶m̶a̶n̶a̶g̶e̶r̶ ̶r̶i̶g̶h̶t̶s̶ ̶i̶f̶ ̶s̶o̶m̶e̶o̶n̶e̶ ̶w̶a̶n̶t̶s̶ ̶t̶o̶ ̶v̶o̶l̶u̶n̶t̶e̶e̶r̶ ̶f̶o̶r̶ ̶t̶h̶i̶s̶ ̶j̶o̶b̶.̶

      Update 1: dmkozyrev volunteer to add some ladders. I created a Public group if anyone wants to add ladders read How to contribute blog.

      Update 2: Access them here. Thanks to @ahmed_aly for creating a2oj platform and @dmkozyrev for creating these mashups.

      • »
        »
        »
        »
        3 months ago, # ^ |
        Rev. 3   Vote: I like it +75 Vote: I do not like it

        Added all ladders from 11 to 21, please check

        UPD. Added ladders from 22 to 31

        • »
          »
          »
          »
          »
          2 months ago, # ^ |
            Vote: I like it 0 Vote: I do not like it

          Thanks dmkozyrev .

        • »
          »
          »
          »
          »
          2 months ago, # ^ |
            Vote: I like it 0 Vote: I do not like it

          The ladders are there... although there is one thing... all the questions in the ladder are from codeforces... but the question opening through your ladders open with some other link.

          This is not a problem actually ; but the issue is that other options which are attached with a problem ( example the tutorial , announcement option ) is missing. Announcement may not be that important ; but I think tutorial is.

          Plus the submission history of the problem is not the actual history of the problem ; it is not showing my previous submissions of the same problem ( If the previous submission of the problem was done through codeforces itself ).

          I don't know if the missing of tutorial option and non-availabilty of previous submissions is some bug or a feature yet to be implemented...

          But it is indeed correct that a2Oj was a life saver and by keeping it alive through some alternate form ; you guys are doing a great job... It would be nice if you could do something about the tutorial option.

          Thanks !

          • »
            »
            »
            »
            »
            »
            2 months ago, # ^ |
              Vote: I like it 0 Vote: I do not like it

            There is another issue with submissions. A test case gives timeout error through this ladder whereas the same question in the problemset passes without an issue.

            Even though it says timeout error, it is able to print out my output. Referring to problem "Mashmokh and ACM" TC#15 in Java.

    • »
      »
      »
      3 months ago, # ^ |
        Vote: I like it 0 Vote: I do not like it

      Man you are the best. Thanks for your 10+ years of work and helping people to improve their coding skills systematically using the online judge. Thanks

  • »
    »
    2 months ago, # ^ |
      Vote: I like it 0 Vote: I do not like it

    ask ahmed sir i too need it..

»
3 months ago, # |
  Vote: I like it +113 Vote: I do not like it

Just a suggestion: Can the ladders be included somehow in Codeforces website. Its a really good collection of problems.

MikeMirzayanov Sir can this be done?

»
3 months ago, # |
  Vote: I like it +3 Vote: I do not like it

Auto comment: topic has been updated by ahmed_aly (previous revision, new revision, compare).

»
3 months ago, # |
  Vote: I like it +130 Vote: I do not like it

why not giving it to someone who can care instead?

»
3 months ago, # |
  Vote: I like it +1 Vote: I do not like it

I was currently using it for improving my skills for div2 C and D problems. This is really a sad newss :(

»
3 months ago, # |
Rev. 2   Vote: I like it +30 Vote: I do not like it
FFFFFFFF
F
FFFFFF
F
F
F
F
»
3 months ago, # |
  Vote: I like it +19 Vote: I do not like it

why i am really sad ! the ladder helped me a lot and still .. i wish you can change your mind

»
3 months ago, # |
  Vote: I like it +3 Vote: I do not like it

I just started using it few weeks ago and its sad to know that it will be closed soon . The ladders was an awesome concept and i am very much thankful for that.

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

M3lsh..

»
3 months ago, # |
  Vote: I like it +93 Vote: I do not like it

The ladders have helped me a lot in progressing (especially the feature about not being able to look at the next problem unless you ac the current one). Thanks for creating it in the first place.

»
3 months ago, # |
  Vote: I like it +23 Vote: I do not like it

Sad to hear this. Your site helped me and my friends a lot. I'm grateful for all the work and effort you've put in. If you decided to do so, then go ahead.

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

seriously Why doesn't Codeforces have Sad reacts? :"(

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

I use this site mostly to find the problem in category.

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

F

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

This site was super helpful for me after I finished USACO training pages. Thanks for making it :) I'm glad you're keeping a static version of the ladders/categories.

»
3 months ago, # |
  Vote: I like it +26 Vote: I do not like it

Open source it.

»
3 months ago, # |
  Vote: I like it +1 Vote: I do not like it

It's very helpful for all programmers because there is a set of problems for all categories, Ladders are so helpful for all programmers also.

»
3 months ago, # |
  Vote: I like it -116 Vote: I do not like it

vjudge >> a2oj

»
3 months ago, # |
Rev. 2   Vote: I like it +2 Vote: I do not like it

End of an era. Thanks man Ahmed

»
3 months ago, # |
  Vote: I like it +93 Vote: I do not like it

Maybe you could find someone willing to host it instead.

»
3 months ago, # |
  Vote: I like it -58 Vote: I do not like it

Kindly do not deactivate! I have just started using it.It is quite useful. Kindly change your mind please.

  • »
    »
    3 months ago, # ^ |
      Vote: I like it +87 Vote: I do not like it

    and also please don't try to convince me to change my mind.

    And I really like how this is not even an elaborate attempt to change their mind, there's no reassuring speech, no "A2OJ has been so important to many", no arguments at all, just "pls change your mind!!"

    • »
      »
      »
      3 months ago, # ^ |
        Vote: I like it 0 Vote: I do not like it

      There are probably so many reasons, that he couldn't list them in a single comment. :)

»
3 months ago, # |
  Vote: I like it -8 Vote: I do not like it

please make an excl sheet of every categories and ladder also. Thanks <3

»
3 months ago, # |
  Vote: I like it -35 Vote: I do not like it

idk but it was the great site for beginners, please don't shut it down :( please.

»
3 months ago, # |
  Vote: I like it +4 Vote: I do not like it

F

»
3 months ago, # |
  Vote: I like it +3 Vote: I do not like it

Ladders help me a lot. I will miss you A2. And thanks for your contribution.

»
3 months ago, # |
  Vote: I like it -8 Vote: I do not like it

If possible please hand it over to someone or rather Codeforces to take care of it and continue updating the website as it has been very helpful to many of us and will be helpful in the future.

Thanks for all the efforts.

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

thanks you so much a2oj

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

how about the chances to re-run a2oj in the future?

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

I can't receive verification email,and it isn't in the spam,is it still working?

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

"I am not crying......"

»
3 months ago, # |
  Vote: I like it +3 Vote: I do not like it

a2oj, ffffffffffffffffffffffffffffff, please make your project open source or give someone who can care about it

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

The ladders have helped me a lot. Thank you so much a2oj we will miss you. Goodbye :(

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

My memories <3 Bye

»
3 months ago, # |
Rev. 2   Vote: I like it +4 Vote: I do not like it

Thanks for 10 years of dedication :((

»
3 months ago, # |
  Vote: I like it +3 Vote: I do not like it

Is it possible to create a group here in CF and then add all ladders as contests, because the problem selection in the ladders is very nice.

»
3 months ago, # |
Rev. 2   Vote: I like it +10 Vote: I do not like it

I am really very sad to hear it. It was a large online judge with problems of tasks from various sources with handy ladders & categories. Your site really helps me and my friends... Thank you for 10 years of hard work!

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

Will miss A20j badly. The ladder have helped me a lot. As you made up your mind, I will respect your decision, but its a request from whole cp community to please make your project opensource. Thank you and good bye A2oj :(

»
3 months ago, # |
  Vote: I like it +23 Vote: I do not like it

Can you please add the contests on the website to the Codeforces Gym? These contests have great value and many people can get benefits from them.

I'm willing to help you with this

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

I wish one day someone will come forward and make something like a2oj and help the newcomers to get the best pathway for better problem solving as it did to me .. #will_miss_u_a2oj.

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

I had been a wanderer in terms of problem solving, with no proper idea or plan on how to practice well to solve more problems in contests. Thus my progression in terms of effective practice had been going down the ranking. Thanks to A2Oj I not only beleived that the ladders would be effective if I solved accordingly, I have also been getting the results.

Thank you so much. Good luck.

»
3 months ago, # |
  Vote: I like it -10 Vote: I do not like it

please please don't do this if you are shutting it down can you please merge it with code forces

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

This site help me alot thanks for your hard work And i wish good for you

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

Auto comment: topic has been updated by ahmed_aly (previous revision, new revision, compare).

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

I am so sad .... A2 Online Judge helped me a lot in my past . Thank you man for every thing you did ahmed_aly .

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

“Say bye .”
"Bye Bye!"

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

Oh no!!!!!!!! That's too sad !!!!!!!!!!!!

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

Thank you for all your hard work. Please accept my gratitude as your ladder helped me alot to overcome and understand how to practice CP.

»
2 months ago, # |
  Vote: I like it +2 Vote: I do not like it

can anyone please explain me what difference will occur after static version.means then also we can access problems and solve them.so what will be difference??

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

I used a2oj during last winter holiday, it helped me gain pretty much CP knowledge and win a gold medal in this year's ICPC, thanks and goodbye.

»
2 months ago, # |
  Vote: I like it +1 Vote: I do not like it

Bye a2oj, you were an incredible online judge and I will solve on you till the last moment

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

A2OJ really helped me a lot in improving my coding skills. Thanks a lot man A2OJ will be remembered forever

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

nooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooo

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

When i found this,I was a beginner! CP was new for me! These ladders are good teachers especially for people like me who give up quite fast when you cant find the solutions in few minutes or hours!but unable to get the next question kept me trying my best to find out the other ways of doing the current question!

much thanks to ahmed! thanks a lot! from--> A BEGINNER !

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

This sounds not good for me. By the way, this site was very helpfull.

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

Would you please export all the ladders ?

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

How can I access all ladders' problems without solving all of them?

  • »
    »
    2 months ago, # ^ |
      Vote: I like it 0 Vote: I do not like it

    Even with solving all, the site didn't count my recent solved problems and I have to wait someone to add Codeforces div2,1 ABCDE ladders to the CF's group

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

ridam dahanetoon thanks...

»
3 weeks ago, # |
  Vote: I like it -13 Vote: I do not like it

apolgy for bad english

where were u wen a2oj die

i was at house eating dorito when phone ring

"a2oj is kil"

"no"

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

where is the static version of ladders?

»
3 weeks ago, # |
  Vote: I like it -8 Vote: I do not like it

how to access the static version of ladders now?

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

Auto comment: topic has been updated by ahmed_aly (previous revision, new revision, compare).

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

Check this post, I hope that community enjoy it this tool to see your progress in the ladders list.

https://codeforces.com/blog/entry/72781