Problems with the challenge question in NOV13

bug
challenge
contest
november
rankings
seavec

#1

I tried to submit the codes of the people who got better score in contest in the practice session.
Their code are giving TLE but my code is running fine.
How are these solutions accepted in the contest giving them a better rank than me.
refer to the following solution links

http://www.codechef.com/viewsolution/2982569

http://www.codechef.com/viewsolution/2982528


#2

Did you make the compiler as same version same?
That c++ has many versions right?
c++ 4.3.2,4.8.1…


#3

My code first gave AC during the contest. but i wanted to know the score,so i submitted it in the practice section. I got AC again. But the solutions got rejudged i guess, i got a tle in the contest challenge but my submission in practice section is still showing AC. I resubmitted the same code in the practice section again today and i’m getting a TLE. Can anyone please explain what’s going on :open_mouth: :open_mouth: I’ll get a 0 even if my solution is accepted but i still want to know why its happening. Besides the algorithm’s time complexity is O(nklogk), i don’t know how that’s showing TLE. Have all the solutions been rejudged?


#4

@admin, please make sure that all submissions are considered. One of my worse submissions is showing higher score than my best submissions. It might be because other submissions haven’t been rejudged but submissions should not be ignored if they are now getting TLE (at least in the practice section).


#5

@admin
What is happening ?
My solution got AC at the time of contest.
Now it is showing TLE ?
How is that even possible?


#6

Rejudging is not taking care of the fact that submissions were accepted during the contest but are getting TLE now. My earlier accepted solutions have been marked with TLE after rejudging. @admin, please look into it.
Further, I suspect the hidden files were very different from the 2 files on which score was shown during the contest, leading to contestants to move away from solutions which could give better score overall towards solutions which gave higher score on the 2 files. This is not fair. Performance on those 2 files should be an indication of performance on the hidden files, otherwise we are just shooting in the dark.


#7

The cases of the AC solutions getting TLE will be looked into. There was some issue in the re-judging the solutions the first time around. We have rejudged them now. However, due to so many solutions getting queued for a rejudge, the load on the online judge increases with resource contention coming into picture. This makes the judge slower and some solutions may get TLE’d. Please do not worry about them as we will try and make sure that all AC solutions during the contest get AC even after rejudge.


#8

My code is giving TLE (http://www.codechef.com/viewsolution/2975079) in the practice section but I got AC with it during the contest and it was getting accepted yesterday in the practice section. What’s going on?


#9

ya…exactly…codes which were earlier running fine during contest are giving TLE…but even then they are counted in the total scores of the users…


#10

yes. I always use c++ 4.3.2.


#11

Well they should be counted. If the contestants were made to believe for 10 days during the contest that their codes ran successfully under the given time constraints, that must not change after the contest. After all, problem setters guaranteed that getting an AC on the challenge problem meant that it would run successfully on the hidden files.
I think they probably added more test cases to the problem version in the practice section.


#12

I think it is because the Codechef servers are now more loaded than during the previous rejudge (and also than when you submitted your code in the Practice section or during the contest). I am also experiencing a similar problem with my top submission. When I resubmitted again today in the Practice section it got 200 points less than before (approx. 3450 pts instead of approx 3650 pts as it should get) - not because of anything random in it, but because I used some time limits and it was able to do less work within those time limits than before.


#13

hmm… So you’re saying the final verdict of my submission may depend on the server load? :confused:


#14

@darkrayshiro: Sadly, that’s what I’m saying. However, could @admin confirm that server load influences the running time of the submissions? I also experienced this in other Codechef contests (the same submission would give TLE at times and there would be no way around it except wait for some time). Did anyone else notice the influence of server load on their submissions in previous contests?


#15

ya…i too use same one


#16

I too had noticed that execution time for the same code at different times differ due to different server load .So it does influence the running time of submission.


#17

@cdev: As I told @darkrayshiro , who had the same problem, I think it’s because during the rejudging the servers where the submissions were rejudged were more loaded than during the contest. Thus, the same code took slightly more time to run (which could lead to TLE). I encountered this behavior in previous Codechef contests. It’s always better to take some precautions against such possibilities. In the future try setting some time limits for your code which, when exceeded, will make your program stop running - this way you’ll be sure to avoid TLE no matter what.


#18

@mugurelionut but some of my submissions are getting AC . These submissions are not taken into account . Why only TLE ones ?
I have got around 20 AC solutions why don’t they pick one of them ?
http://www.codechef.com/NOV13/status/SEAVEC,cdev
For example like this
http://www.codechef.com/viewsolution/2953224
http://www.codechef.com/viewsolution/2952532
http://www.codechef.com/viewsolution/2952450