anup.kalbalia's blog

Invitation to the July Cook-off on CodeChef
By anup.kalbalia, 13 years ago, In English

CodeChef invites you to participate in the July CookOff Challenge at http://www.codechef.com/COOK12

Time: 2130 hrs 24th July 2011 to 0000 hrs, 25th July 2011 (Indian Standard Time - +5:30 GMT)
Details: http://www.codechef.com/COOK12/
Registration: Just need to have a CodeChef user id to participate. New users please register here
Problem Setter: Shilp Gupta

It promises to deliver on an interesting set of algorithmic problems with something for all.
The contest is open for all and those, who are interested, are requested to have a CodeChef userid, in order to participate.

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13 years ago, # |
← Rev. 2   Vote: I like it 0 Vote: I do not like it
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13 years ago, # |
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Just for convenience: we can see world time here
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13 years ago, # |
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These contests are getting worse every month, last two were literally impossible to solve for java coders.
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  • 13 years ago, # ^ |
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    Well, I had to optimise in "Please Chief", but I'm not sure C++ solution will pass wthout that optimisations...
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  • 13 years ago, # ^ |
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    I fully agree with you. Codechef becomes worse and worse. This month contests were about how to compress one's solution to get "Accepted".
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  • 13 years ago, # ^ |
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    I completely agree. I wonder why the admins are not doing anything about it. Especially with the time limits. The most obvious solution for "Please Chief" : http://www.codechef.com/viewsolution/605870 is accepted. I compared values for example of C[100][50] with Cdouble[100][50] and the difference was huge (many of last digits were 0). So I thought that it is wrong and tried to compute probability pr[i][j] that item i is on position j, and got TLE... http://www.codechef.com/viewsolution/605873


    Edit.: The point is that in my solution each value is correct and it's obvious that some rounding errors can occur at the last digits of the result, but they don't affect the first 3 digits. But it is tled and to get acc you should use incorrect values counted in Cdouble, with no idea how can the final result be correct.
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    • 13 years ago, # ^ |
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      The values Cdouble are correct with relative error 1e-14. So when we multiply and divide them as in obvious solution the result also will be correct with relative error 1e-14 (or near). But since this value is now less then one. Then relative error becomes absolute. That's why answer is correct.
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  • 13 years ago, # ^ |
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    This is all because of me :P
    Last time I was the author.
    This time I am the tester.
    But I sure you that when I set the time limits I think that they are generous enough.
    I have no aims for the contestants do some nasty optimizations.
    I apologize for all inconviences.
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    • 13 years ago, # ^ |
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      > I have any aims for the contestants do some nasty optimizations.
      Sometimes typos can tell us a lot ;) .
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      • 13 years ago, # ^ |
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        :) update it. It is all because of Russian constructions with two negations which have unsual translate in English.
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    • 13 years ago, # ^ |
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      Dear Sir,

      Can you please help and check if my solution during the contest had the correct solution in java. I had used memoization. I got TLE. My complexity was O(N*K). I coded the same thing in C++ with memoization got TLE there too. Then with standard Dp again got TLE. Then I coded in C++ and used sliding window DP which passed in which I reduced the whole table to only 2 rows.


      My solution during contest.


      This solution passed in C++.
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13 years ago, # |
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We agree that there have been time limit specific glitches in judging specially when it comes to non-native language submissions.

It is really nice of Anton to try and take all the blame on himself as he has a very deep sense of accountability towards the programming community. However, we do not believe that he is responsible in any way for the above glitches that you faced in the recent contests.

Let me admit that we at CodeChef are still learning the nuances of the short contest format. There have been issues which caused inconvenience to the community and we apologize to you all. We will certainly look into them and work towards resolving them. We hope to have you all there in the next contest. And please drop in a mail to feedback@codechef.com in case you feel we can do something to make things easier and better for you.
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  • 13 years ago, # ^ |
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    I have been competing on codechef for more than an year now. I have learnt a lot(thanks a lot for that) but sometimes codechef problems require nasty optimizations specially when it comes to java. For long contest its still ok but for short contest I seriously feel the only thing that should be checked should be the complexity of the solution. It already makes the contestants consume a lot of time in coming up with the solution (at least the new learning coders) if they have to do a lot of optimisations also its really difficult to perform well and it is a bit demoralizing when you see the correct solutions.
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