.PEIN.'s blog

A new Online Judge
By .PEIN., 13 years ago, In English

Recently a online judge has been made public named LIGHTOJ created by JANE ALAM JAN ( acm icpc world finalist ). It is still under development but it looks like a good place for beginners to start their journey. All Problems here are categorized. Also has a good looking interface. It has built in online compiler that supports C, C++, PYTHON, PASCAL, JAVA. The site has built in forum and chat rooms. The facility of virtual contest is also there. Virtual contests can be arranged with your own problem set. The interface might look a bit overwhelming at first.  If you are interested, you can check it out. J

P.S. Please provide your full name and institution when you register.

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13 years ago, # |
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Not only for beginners ..... there are many advance problems. The problems are of various difficulties. And more over it has a training section which will be enriched with useful articles later on. You can also lock a problem after solving it . Locking a problem provides the opportunity of comparing your solution idea with other coders solution and with the judge solution. The most fascinating thing is the web compiler :) :) :). you do not need any compiler installed to code. Currently it supportes C,C++,python,java, pascal(more to come).  
It is the ultimate online judge i think :) :) :)
I invite you all to the world of Lightoj :)

   
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  • 13 years ago, # ^ |
      Vote: I like it -8 Vote: I do not like it
    You can also save your Template in the compiler for default usage.
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13 years ago, # |
  Vote: I like it -9 Vote: I do not like it
wow!! LightOJ is one of the best problem solving site I have ever seen. 
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13 years ago, # |
  Vote: I like it +8 Vote: I do not like it
Tried to register. Name of University didn't pass unless I removed space bars and quotient marks.
I'm still waiting for confirmation of registration. But everything else, seems to be, works perfectly!
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  • 13 years ago, # ^ |
    ← Rev. 2   Vote: I like it -7 Vote: I do not like it

    I think your registration is confirmed by now.

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  • 13 years ago, # ^ |
      Vote: I like it -8 Vote: I do not like it
    Did you confirm your email address? And what is your university name?
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13 years ago, # |
← Rev. 3   Vote: I like it +11 Vote: I do not like it

I was really surprised by functional of that web site.

I saw result of a lot of author effort. He combined a lot of cool features in one place.

It's look cool, but sometimes i understand, that web site is overload. Too much not really important features, but most important pages for customer are placed in really unexpected places. Some ambiguous link captions. Page with FAQ was located only at forum. Very strange, i think.

I think, for beginners will be not easy to start.

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  • 13 years ago, # ^ |
      Vote: I like it -10 Vote: I do not like it
    Lightoj has only just started its journey. So We should expect that many changes and upgrades will occur (regrading background system and the front side system).
     Please keep sharing you thoughts.
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13 years ago, # |
  Vote: I like it +8 Vote: I do not like it
I don't like how it didn't ask me to specify password and that there's no feature for restoring password =|
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  • 13 years ago, # ^ |
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    You password should be mailed to your email address. You can always change your password by going to "My Info".
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13 years ago, # |
← Rev. 4   Vote: I like it -11 Vote: I do not like it
Please share you views about lightoj :)
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13 years ago, # |
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Ok, I confess that I am an idiot, but what are rules for java solutions? I could not find them! I see that file being compiled is called Main.java, but I anyway could not use class "public class Main" because "it should be declared in its own file".

It seems slightly not self-evident for me...

It looks that up to now CodeForces is one of few resources which do not have restrictions for java class names in solution.
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  • 13 years ago, # ^ |
      Vote: I like it +1 Vote: I do not like it
    class Main, not public class Main

    Anyway the site is not great - I want to know test number if my program is not correct, but it doesn't show me!
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    • 13 years ago, # ^ |
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      Thank you for advice. Now the problem got "Memory limit exceeded"... I suppose that java tester is not very finely tuned... I do not know what they mean by 32Mb - heap memory or memory stolen by the whole JVM...

      Yes, there are no numbers of failed testcase. I would say that the work of resource author is great, but it should be greater if he wants to make it popular internationally.
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    • 13 years ago, # ^ |
      ← Rev. 2   Vote: I like it +2 Vote: I do not like it

      lightoj maintains ACM ICPC standard So you can not see the testcase number for which you code is not getting AC.

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      • 13 years ago, # ^ |
          Vote: I like it +3 Vote: I do not like it
        Ah, thank you! Though it would be better to create small FAQ about all this things...
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        • 13 years ago, # ^ |
            Vote: I like it +1 Vote: I do not like it
          yes :) Lightoj just  started its journey .... So many changes and upgrades will occur (regrading background system and the front side system).
          Please keep sharing you thoughts so that lightoj can be improved by time :) :).
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      • 8 years ago, # ^ |
          Vote: I like it -33 Vote: I do not like it

        Do You know if in ICPC regional judge answer is after running all test cases, or they only run until a testcase where it fails?

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13 years ago, # |
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Funny, but I can not register, my proxy server cuts captcha :(, so I like sound captcha more
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13 years ago, # |
← Rev. 2   Vote: I like it +1 Vote: I do not like it

LightOJ has just started it's journey. And there is more to implement there. Please give your suggestion in forum. Your suggestion is valuable for us. And sorry for inconvenience.


It's mainly a beginner site. Who loves to solve problem. All the problem are well categorized, So its easy for beginners to pick the categorized problems and learn the algorithm step by step.  
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13 years ago, # |
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In Java, I used System.out.printf("Example: %f + %f = %f (of course)", a, b, c) and it didn't work!
(output like that: "Example:  +   =  (of course)", it didn't print value of a, b and c)

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  • 13 years ago, # ^ |
      Vote: I like it +1 Vote: I do not like it
    what's the type of a, b and c? is it double? did you try using %lf insted of %f?
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    • 13 years ago, # ^ |
      ← Rev. 3   Vote: I like it 0 Vote: I do not like it

      Thanks for your recommend :)
      My code is like that:
              double a = 3.5;
              double b = 6.3;
              double c = a + b;
              System.out.printf("Example: %f + %f = %f (of course)", a, b, c);
      When I try using %lf, it returned Runtime Error :(

      You can check here: http://www.lightoj.com/compiler_volume.php

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      • 13 years ago, # ^ |
          Vote: I like it +1 Vote: I do not like it
        Try to use PrintWriter and his method printf with locale and precision (%.nf), where n-number of digits after dot.
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        • 13 years ago, # ^ |
            Vote: I like it 0 Vote: I do not like it
          Here is my source code and it still didn't run :(

          import java.util.*;
          import java.io.*;
          public class Main {
              public static void main(String[] args) {
                  PrintWriter out = new PrintWriter(System.out);
                  double a = 4.5;
                  double b = 6.3;
                  double c = a + b;
                  out.printf("Example: %.2f + %.2f = %.2f (of course)", a, b, c);
                  out.close();
              }
          }
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13 years ago, # |
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check this :
the compiler uses gcj-java and it has a bug :

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  • 13 years ago, # ^ |
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    It was a very bad idea to use GCJ for Online Judge, I suppose.
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12 years ago, # |
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lightoj Is really an awesome site for practicing. Thanks to Jane Alam Jan for such a gift for all programmers.
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12 years ago, # |
  Vote: I like it +3 Vote: I do not like it
The thing i like about lightoj is that once you solve the problem and lock it you can view the author's solution and all the submitted solutions. This really helps beginners improve their coding. Also the categorization of problems is really awesome. Thanks for lightoj
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