ahmed_aly's blog

Codeforces Practice Ladders — A2 Online Judge
By ahmed_aly, 9 years ago, In English

Recently I added a new feature in A2 Online Judge, it's called Practice Ladders. A practice ladder is just a list of problems, and you can add some dependencies between the problem (for example, you must solve problem X before being able to see problem Y). Also you can add dependencies between the ladders and each other (for example, you must solve all problems in ladder X before being able to see any problem in ladder Y).

Also I created 7 Codeforces practice ladders which should you to increase your level, each ladder contains 100 Codeforces problems. Find which ladder is appropriate for you and enjoy!

Div. 2 A Problems: http://a2oj.com/Ladder.jsp?ID=4

Div. 2 B Problems: http://a2oj.com/Ladder.jsp?ID=5

Div. 2 C Problems: http://a2oj.com/Ladder.jsp?ID=6

Div. 2 D Problems: http://a2oj.com/Ladder.jsp?ID=7

Div. 2 E Problems: http://a2oj.com/Ladder.jsp?ID=8

Div. 1 D Problems: http://a2oj.com/Ladder.jsp?ID=9

Div. 1 E Problems: http://a2oj.com/Ladder.jsp?ID=10

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Comments Comments (63)
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9 years ago, # |
← Rev. 2   Vote: I like it 0 Vote: I do not like it

Can I solved Div. 2 A Problems directly before the practice ladders id 1,2,3 ?

I tried to solve practice ladders id 4 , but I am not getting where I have to submit the solution?

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    9 years ago, # ^ |
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    To solve problems from any ladder, you have to just go to the problem link, which will direct you to the actual problem link on Codeforces. You, then solve the problem as usual and after getting it accepted, go to your profile on A2oj and update Codeforces profile there, next problem will be automatically unlocked in the same ladder.

    Hope this helps.

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9 years ago, # |
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Hello, the idea is awesome, thanks! Can you check the Div2 D's ladder second problem, please? Actually, it is a Div2 B problem, not D, and I got AC twice and it doesn't count it as solved.

PS: I have clicked the update button.

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

This feature is very nice, interesting and also motivational. I think this feature helps me to select the problems for practise. Thank you ahmed_aly

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9 years ago, # |
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Thanks... That's a great feature.
I think it makes better, If people can filter or change the priority of problems in a ladders for themselves.

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9 years ago, # |
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How about ladder for SPOJ? It has a very good collection of problems, but it is a mess. Could you please add that feature? It will be very helpful. :)

By the way, thank you very much for this wonderful feature.

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9 years ago, # |
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Thank you for this wonderful feature. I have one request, once I complete a ladder the ladder should be highlighted in green (similar to accepted problem) on the ladders page.

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9 years ago, # |
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Great Work :)

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9 years ago, # |
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Hello ahmed_aly,

It is taking too much time to update the problem that you have solved in the list. Can there be some improvement ?

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    9 years ago, # ^ |
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    Actually you need to update it manually.

    Just go to your profile and click "update".

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9 years ago, # |
← Rev. 3   Vote: I like it +12 Vote: I do not like it

Is the judge currently down ? presently I am unable to access.
UPD : It's working now :)

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9 years ago, # |
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The system a2oj is down again!!!

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    9 years ago, # ^ |
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    It should be back now. Sorry for any inconvenience.

    -- Ahmed Aly

    www.a2oj.com

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9 years ago, # |
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Thanks a lot this offers us (beginners) much help !

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9 years ago, # |
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Now nobody can login on the system!!!

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9 years ago, # |
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why I have to log in after every 15 minute ? it keeps me continuously logged out from a2oj.com after every 15 minute though I checked the Remember me checkbox .

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9 years ago, # |
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I am getting HTTP Status 500 — java.lang.NullPointerException in Div2 D ladder.

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9 years ago, # |
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Its showing me This username doesn't exist O.o

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8 years ago, # |
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Sorry, but the ladder does not work. When I updated, the red text saying " Your solved problems for this ladder will be updated within few minutes ", and the next problem is hidden. Waited a few days, no changes.

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    8 years ago, # ^ |
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    Did you updated your codeforces handle under "My Account" on A2 site and then updated the solved problems list on the ladder page ?

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8 years ago, # |
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Is there's some problem with a2oj.com right now?

it keep telling me that username doesn't exist!!!

is it only me?

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    8 years ago, # ^ |
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    Nope not only you. Same is with me. I hope it can be recovered soon :\

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    8 years ago, # ^ |
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    A2 Online Judge is back. I'm really sorry for the delay.

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8 years ago, # |
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is a2oj down right now when will it get fixed???

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    8 years ago, # ^ |
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    A2 Online Judge is back. I'm really sorry for the delay.

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8 years ago, # |
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Any update on when a2oj is coming back??

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    8 years ago, # ^ |
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    A2 Online Judge is back. I'm really sorry for the delay.

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8 years ago, # |
← Rev. 2   Vote: I like it +6 Vote: I do not like it

when a2oj will be back again ??? any update ????

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    8 years ago, # ^ |
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    A2 Online Judge is back. I'm really sorry for the delay.

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      8 years ago, # ^ |
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      it still doesn't update SPOJ, Timus problem list.

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8 years ago, # |
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ahmed_aly Can i save pages of A2OJ on Internet Archive, so that if it goes down we can reuse the saved pages from Internet Archive ???

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8 years ago, # |
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A2OJ isn't updating my solved problems for Codeforces. :( Please fix the bug.

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    8 years ago, # ^ |
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    Did you change your handle?? If so you have to update it in the website also.

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      8 years ago, # ^ |
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      oh !! thanks a lot !! i forgot that !!

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8 years ago, # |
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ahmed_aly I'm sorry to bother, it's just that my A2OJ account is signing me in with another account. First everything works fine, but when I click on My Account it changes my account to another account, can you help me with this?

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8 years ago, # |
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is site down right now ?? or i am the only one facing the problem ??

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    8 years ago, # ^ |
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    seems like the site is down. i can't access too. :(

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    8 years ago, # ^ |
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    It's back now. Sorry I made a mistake yesterday just before sleeping while fixing some stuff.

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8 years ago, # |
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Hi, when I go to "My Account" and try to add my SPOJ account it always says "This is invalid SPOJ username", can you fix that? My accounts for a2oj and spoj are both Secta if you need this info :)

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8 years ago, # |
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I am not able to use it.Can some one say me how to use because I have updated my account there and so it is showing only the first question.

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    8 years ago, # ^ |
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    you must solve first problem to show the second and solve the second to show third...... or you mean that you solve it and now it is unavailable ???

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8 years ago, # |
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A2OJ is down ... When will it be back ??

it will be very helpful if anyone could provide me with problems in each ladder if there is still much time before working again.

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8 years ago, # |
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Why the site is not working? It is down and when it will be working?

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8 years ago, # |
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If anybody has a screen-shot of the DIV2D ladder problems , please share it as the site is down.

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7 years ago, # |
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I started doing Div C (ladder Id=6) yesterday and completed the first question but still the second question is hidden!! I have tried clicking on the "Update" button,it says it will take a few minutes but still it isnt getting updated. Can you please help.

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    7 years ago, # ^ |
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    Does you link your codeforces handle with A2OJ?

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      7 years ago, # ^ |
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      how to link my handle to A2Oj?

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        7 years ago, # ^ |
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        On the top of the site next to your username click on "My Account". Then scroll down and find a field named "Codeforces Handle" write your handle there. Don't forget to update your data :)

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

the ladder do not count the problem that I solve anymore that happened at the problem 24 so I can not go any more for a new problems note : my data at "a2oj" site is right... what should I do ???

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5 years ago, # |
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Extremely helpful. Thanks a lot G!

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4 years ago, # |
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Great work. But the ladder take so long to update. Would anyone please provide me screenshot of their solved ladder C (div2) so that i can personally solve all ladder problems without waiting.

That would be great. Thanks in advance https://a2oj.com/ladder?ID=6 @ahmed_aly

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4 years ago, # |
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It takes too long to update on a2oj ladders. I've solved Div2D problem 1 and now it's been almost 25 mins and still it has not updated it. Please resolve this issue ASAP.

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4 years ago, # |
← Rev. 2   Vote: I like it +4 Vote: I do not like it

Can we get static ladders back?

Found : https://codeforcesladders.firebaseapp.com/

If anyone is interested in ladders may use it.

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    4 years ago, # ^ |
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    thank you my dude.. very helping.. here, take my upvote..

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4 years ago, # |
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Are there any particular timings in which A2oj will be working?

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3 years ago, # |
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I can't see my solved problems marked as green on a2oj. They are not getting updated as earlier, any suggestions?

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3 years ago, # |
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i am getting "HTTP Status 500 – Internal Server Error".

please help. how do i fix it.

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