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Codechef Rating Predictor

60
21

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, 02:16

vsp4's gravatar image

6★vsp4
1.2k128
accept rate: 28%

edited 09 Jul, 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, 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, 22:53) harishm174★
3

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

(26 Jun, 04:09) prakhariitd6★

where can I see ratings for SEP17?

(02 Sep, 18:03) shubham08124★

@shraeyas thanks!

(02 Sep, 22:07) shubham08124★

the page of Ratings for OCT17 is showing invalid?

(06 Oct, 16:47) shubham08124★
showing 5 of 9 show all

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

link

answered 09 Jun, 07:59

vicennial's gravatar image

5★vicennial
2594
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!!

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answered 09 Jun, 02:24

abdullah768's gravatar image

5★abdullah768
1.2k11
accept rate: 13%

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

Error: No contest predictions found for such contest!

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answered 28 Oct, 23:17

abhipso's gravatar image

5★abhipso
434
accept rate: 0%

edited 28 Oct, 23:20

Please make the NOV COOKOFF predictor.

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answered 19 Nov, 22:46

prakhar17252's gravatar image

5★prakhar17252
203
accept rate: 0%

Awesome tool buddy :)

link

answered 09 Jun, 10:34

godslayer12's gravatar image

3★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?

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answered 09 Jun, 20:26

saisurya027's gravatar image

4★saisurya027
1556
accept rate: 0%

2

Just press ctrl+f and enter your name.

(09 Jun, 20:30) abdullah7685★
1

Thanks a lot

(09 Jun, 20:35) saisurya0274★

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

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answered 09 Jun, 22:29

nuclode's gravatar image

4★nuclode
762
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, 13:29

c0derahul's gravatar image

3★c0derahul
111
accept rate: 0%

edited 10 Jun, 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, 16:19

dkp11's gravatar image

3★dkp11
11
accept rate: 0%

nice job mate :D

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answered 16 Jun, 19:42

shubho666's gravatar image

3★shubho666
9
accept rate: 0%

Currently the links say "Application not available". Excellent work by the way, I used the predictor during the June Long Challenge and it was very accurate in my case, appreciate the time you put into this.

link

answered 19 Jun, 00:53

spar5h's gravatar image

5★spar5h
111
accept rate: 0%

Hi, I believe this error is somehow due to free resources exhaustion. Refreshing a few times works though. Temporarily, I also uploaded latest generated ranklist here: https://codechefratingpredictor.now.sh/

(19 Jun, 01:13) vsp46★

Exactly accurate (100%) :D

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answered 19 Jun, 06:51

final_hacker's gravatar image

2★final_hacker
132
accept rate: 0%

Awesome work buddy!

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answered 19 Jun, 20:32

bens59's gravatar image

3★bens59
314
accept rate: 0%

Awesome work buddy!

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answered 23 Jun, 10:06

ganesh5's gravatar image

3★ganesh5
292
accept rate: 0%

Nice one yaar

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answered 23 Jun, 10:07

syamphanindra's gravatar image

3★syamphanindra
712
accept rate: 0%

loved it thank u codechef ,,very useful

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answered 24 Jun, 20:51

anirudh200602's gravatar image

3★anirudh200602
111
accept rate: 0%

I hope July17 comes out too. Great work.

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answered 08 Jul, 12:06

nileshjha19's gravatar image

3★nileshjha19
1105
accept rate: 0%

August17?

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answered 18 Aug, 19:02

vasja's gravatar image

4★vasja
51516
accept rate: 7%

link

answered 19 Nov, 23:42

lokesh2002's gravatar image

4★lokesh2002
616
accept rate: 0%

It works now.

(20 Nov, 01:03) bazsi7006★

but the links are showing 504 GATEWAY error

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answered 09 Jun, 05:27

vivek7415's gravatar image

3★vivek7415
1
accept rate: 0%

You can try now. That was due to almost all available resources being used in calculation phase. I modified script to use less resources, so this error shouldn't be occurring frequently now

(09 Jun, 19:58) vsp46★

starred on github. Nice work dude.

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answered 10 Jun, 10:59

swamicoder's gravatar image

4★swamicoder
2337
accept rate: 11%

That's some amazing work man :)

link

answered 17 Jun, 01:13

shubhshrma's gravatar image

3★shubhshrma
1
accept rate: 0%

great dude! really useful.

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answered 19 Jun, 11:34

ricksr's gravatar image

3★ricksr
161
accept rate: 6%

Very useful!! Great initiative!

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answered 19 Jun, 11:46

xerefic's gravatar image

3★xerefic
613
accept rate: 0%

Amazing app..shows perfect prediction

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answered 19 Jun, 11:46

harishm17's gravatar image

4★harishm17
10018
accept rate: 15%

Amazing app..shows perfect prediction

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answered 19 Jun, 11:46

harishm17's gravatar image

4★harishm17
10018
accept rate: 15%

Awesome man :).

A humble suggestion: Mark the positive rating changes with a green color and a + sign. Likewise mark the negative with red and a - sign. :)

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answered 24 Jun, 23:01

vasja's gravatar image

4★vasja
51516
accept rate: 7%

WOW! This is 100% accurate! Great work.

link

answered 25 Jun, 11:00

akashbhalotia's gravatar image

3★akashbhalotia
39911
accept rate: 0%

Great Work with great accuracy.

link

answered 10 Jul, 16:07

droy0528's gravatar image

4★droy0528
956
accept rate: 20%

Is there an extension for this like there is one for the cf predictor?

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answered 18 Jul, 21:59

ameyanator's gravatar image

4★ameyanator
0
accept rate: 0%

For those who cannot find the links for latest like me, just copy paste the give link , and change the contest name

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answered 24 Jul, 19:55

abhash_yadav's gravatar image

3★abhash_yadav
413
accept rate: 0%

At present for COOK84 it is showing same username 2 times. Once for current rating and other for initial rating (1500). Is it a bug or a new feature? :D

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answered 25 Jul, 16:59

ak_d's gravatar image

4★ak_d
1
accept rate: 0%

Bug fixed. The records having correct previous rating were actual predictions.

(26 Jul, 11:42) vsp46★

Where can I see the predictions for COOK84?

(27 Jul, 16:18) nileshjha193★

Open the COOK83 link and change COOK83 to COOK84 in the URL

(02 Aug, 23:54) ak_d4★

Why isn't it updated for July lunchtime?

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answered 31 Jul, 19:19

vaibzz's gravatar image

3★vaibzz
112
accept rate: 0%

It is: http://codechef-rating-predictor.7e14.starter-us-west-2.openshiftapps.com/contest/LTIME50/all/ The links for other contests would also be in same format by just changing the contest code

(01 Aug, 11:50) vsp46★

September17 lunchtime rating predictor ?? please thanks

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answered 30 Sep, 20:39

geforce's gravatar image

1★geforce
445
accept rate: 0%

October 17 rating predictor please ??? . Thanks in advance.

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answered 11 Oct, 12:22

geforce's gravatar image

1★geforce
445
accept rate: 0%

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answered 15 Oct, 13:52

vijayiota77's gravatar image

4★vijayiota77
1444
accept rate: 3%

Does codechef decrease your rating if i have a wrong attemp on a question but i am not on the ranklist. ThankYou

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answered 28 Oct, 23:02

subham911's gravatar image

4★subham911
83
accept rate: 0%

@subham911 yes,they decrease the rating..this happened to me in previous Lunchtime you can see my graph for confirmation..

link

answered 28 Oct, 23:12

am10's gravatar image

5★am10
354
accept rate: 0%

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question asked: 09 Jun, 02:16

question was seen: 10,463 times

last updated: 11 Dec, 15:43