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Codechef Rating Predictor

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Hello everyone!

alt text

Codechef Rating Predictor

The delay in previous month rating changes + inspiration from CF Predictor and for the practice of a web-application, i tried to write a script that can predict rating changes from ongoing live contests @ Codechef.

While the actual delays in rating changes s/would be fixed, this script can help in predicting rating changes as new submissions are made, so hopefully it can be useful for Long contests :).

The script is written in nodejs and is based on open rating formulas available at this link. The code for the project can be accessed here

Website is currently hosted on Openshift free servers and has few restrictions on use. Therefore the server might be slow or not responding during the period rating changes are calculated. Currently, ratings are expected to be updated every 15 minutes

I also tested rating changes on few past contests and the predictions were accurate within an error of 2 for almost everyone except the first rank (I have no idea why first rank predictions are wrong in some contests using current formulas)

Please note that project is still in beta stage and also actual changes might differ more due to changes in ranklist after plagiarism detection

Your feedback/suggestions would be appreciated

JUNE17 Links:

All: http://codechef-rating-predictor.7e14.starter-us-west-2.openshiftapps.com/contest/JUNE17/all/

Long: http://codechef-rating-predictor.7e14.starter-us-west-2.openshiftapps.com/contest/JUNE17/long/

Few stats on JUNE17 Predictions. I matched ratings (All) of first 6391 users and the results were as follows:

Difference - No of users

  • 0 - 5868
  • 1 - 275
  • 2 - 125
  • 3 - 68
  • >= 4 - 55

There were around 40 users having difference > 50. Turns out some usernames appears to be missing in the ranklist when sorted by rank and hence they were showing as last in the prediction list.

I ran the code again after fixing the above bug and results are better now (Maximum difference is 8)

  • 0 - 5900
  • 1 - 485
  • >= 2 - 6

COOK83 Links:

All: http://codechef-rating-predictor.7e14.starter-us-west-2.openshiftapps.com/contest/COOK83/all/

Short: http://codechef-rating-predictor.7e14.starter-us-west-2.openshiftapps.com/contest/COOK83/short/

The ratings are expected to update every 5 minute

Few stats, 4811/4820 predictions (for both all and cook-off predictions) were right. Rest have diff < 3 with the exception of rating prediction of first rank in cook off. Also, as @vikasj554 pointed out, few users got rating changed after initial update. (I still need to figure out why this happened). But even after this 4794/4820 predictions were accurate.

LTIME49 Links:

All: http://codechef-rating-predictor.7e14.starter-us-west-2.openshiftapps.com/contest/LTIME49/all/

Lunchtime : http://codechef-rating-predictor.7e14.starter-us-west-2.openshiftapps.com/contest/LTIME49/ltime/

The ratings are again expected to update every 5 minute

JULY17 Links:

All: http://codechef-rating-predictor.7e14.starter-us-west-2.openshiftapps.com/contest/JULY17/all/

Long : http://codechef-rating-predictor.7e14.starter-us-west-2.openshiftapps.com/contest/JULY17/long/

Update frequency: 10 mins

asked 09 Jun '17, 02:16

vsp4's gravatar image

6★vsp4
1.2k128
accept rate: 28%

edited 09 Jul '17, 18:10

1

@vsp4 hey bro, just wanted to inform you that for some users like @uwi and @lg5293 rating was calculated again by codechef , i guess. because earlier they got a negative rating like your tool calculated. but now their rating has changed. and for uwi your tool's rating and original rating mis-match by 128 points.

(23 Jun '17, 15:30) vikasj5544★
2

Please do the same for Junior rankings also...that would of great help to all of us..Great job on the tool..Congratulations.

(24 Jun '17, 22:53) harishm171★
3

Isn't there a permanent link, so that you don't have to edit it?

(26 Jun '17, 04:09) prakhariitd6★

where can I see ratings for SEP17?

(02 Sep '17, 18:03) shubham08121★

@shraeyas thanks!

(02 Sep '17, 22:07) shubham08121★

the page of Ratings for OCT17 is showing invalid?

(06 Oct '17, 16:47) shubham08121★
1

rating predictor for LTIME55 not available?

(30 Dec '17, 20:47) lokesh20024★

@vsp4 UPDATE rating predictor for march18a,march18b;

(05 Mar, 11:00) lokesh20024★
showing 5 of 11 show all

123456next »

The CF predictor was/is incredibly useful. I imagine this would be too.
Nice work! :)

link

answered 09 Jun '17, 07:59

vicennial's gravatar image

6★vicennial
2595
accept rate: 0%

That is brilliant work! I always wonder what my rank would be after the contest but codechef's delays leave me checking in everyday only to find out the ratings have not been updated.

Thanks a lot, buddy!!

link

answered 09 Jun '17, 02:24

abdullah768's gravatar image

6★abdullah768
1.8k217
accept rate: 16%

Prediction for October Lunchtime (LTIME53) is not working. It is showing the error

Error: No contest predictions found for such contest!

link

answered 28 Oct '17, 23:17

abhipso's gravatar image

4★abhipso
434
accept rate: 0%

edited 28 Oct '17, 23:20

Please make the NOV COOKOFF predictor.

link

answered 19 Nov '17, 22:46

prakhar17252's gravatar image

5★prakhar17252
603
accept rate: 0%

Awesome tool buddy :)

link

answered 09 Jun '17, 10:34

godslayer12's gravatar image

1★godslayer12
41910
accept rate: 7%

Excellent Work.And one small suggestion can you sort the names if possible or is there any way to find my username quickly?

link

answered 09 Jun '17, 20:26

saisurya027's gravatar image

4★saisurya027
1666
accept rate: 0%

2

Just press ctrl+f and enter your name.

(09 Jun '17, 20:30) abdullah7686★
1

Thanks a lot

(09 Jun '17, 20:35) saisurya0274★

Amazing Work Now really don't need to much worry about my ratings change.

link

answered 09 Jun '17, 22:29

nuclode's gravatar image

4★nuclode
763
accept rate: 16%

according to this I'll be loosing 31 points at the moment...
but great job!!!
good way to get a fair warning.

link

answered 10 Jun '17, 13:29

c0derahul's gravatar image

1★c0derahul
212
accept rate: 0%

edited 10 Jun '17, 13:30

Very nice work. To be honest, once I thought of doing this, guess I don't need to now :). Your work is amazing. Thanks, we needed this.

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answered 16 Jun '17, 16:19

dkp11's gravatar image

2★dkp11
11
accept rate: 0%

nice job mate :D

link

answered 16 Jun '17, 19:42

shubho666's gravatar image

3★shubho666
9
accept rate: 0%

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question asked: 09 Jun '17, 02:16

question was seen: 20,688 times

last updated: 2 days ago