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# Codechef Rating Predictor

 60 21 Hello everyone! 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: 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: 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: The ratings are again expected to update every 5 minute JULY17 Links: Update frequency: 10 mins asked 09 Jun, 02:16 6★vsp4 1.2k●1●2●8 accept rate: 28% 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) 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) 3 Isn't there a permanent link, so that you don't have to edit it? (26 Jun, 04:09) where can I see ratings for SEP17? (02 Sep, 18:03) (02 Sep, 21:10) shraeyas2★ @shraeyas thanks! (02 Sep, 22:07) the page of Ratings for OCT17 is showing invalid? (06 Oct, 16:47) (14 Oct, 16:36) 2 Hey @vsp4, the ratings in the site is not updated for DEC17. Link: http://codechef-rating-predictor.7e14.starter-us-west-2.openshiftapps.com/contest/DEC17/long/ and codechef-rating-predictor.7e14.starter-us-west-2.openshiftapps.com/contest/DEC17/all/ (11 Dec, 15:43) showing 5 of 9 show all

 5 The CF predictor was/is incredibly useful. I imagine this would be too. Nice work! :) answered 09 Jun, 07:59 259●4 accept rate: 0%
 2 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!! answered 09 Jun, 02:24 1.2k●11 accept rate: 13%
 2 Prediction for October Lunchtime (LTIME53) is not working. It is showing the error Error: No contest predictions found for such contest! answered 28 Oct, 23:17 5★abhipso 43●4 accept rate: 0%
 2 Please make the NOV COOKOFF predictor. answered 19 Nov, 22:46 20●3 accept rate: 0%
 1 Awesome tool buddy :) answered 09 Jun, 10:34 419●10 accept rate: 7%
 1 Excellent Work.And one small suggestion can you sort the names if possible or is there any way to find my username quickly? answered 09 Jun, 20:26 155●6 accept rate: 0% 2 Just press ctrl+f and enter your name. (09 Jun, 20:30) 1 Thanks a lot (09 Jun, 20:35)
 1 Amazing Work Now really don't need to much worry about my ratings change. answered 09 Jun, 22:29 4★nuclode 76●2 accept rate: 16%
 1 according to this I'll be loosing 31 points at the moment... but great job!!! good way to get a fair warning. answered 10 Jun, 13:29 11●1 accept rate: 0%
 1 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. answered 16 Jun, 16:19 3★dkp11 11 accept rate: 0%
 1 nice job mate :D answered 16 Jun, 19:42 9 accept rate: 0%
 1 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. answered 19 Jun, 00:53 5★spar5h 11●1 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★
 1 Exactly accurate (100%) :D answered 19 Jun, 06:51 13●2 accept rate: 0%
 1 Awesome work buddy! answered 19 Jun, 20:32 3★bens59 31●4 accept rate: 0%
 1 Awesome work buddy! answered 23 Jun, 10:06 3★ganesh5 29●2 accept rate: 0%
 1 Nice one yaar answered 23 Jun, 10:07 71●2 accept rate: 0%
 1 loved it thank u codechef ,,very useful answered 24 Jun, 20:51 11●1 accept rate: 0%
 1 I hope July17 comes out too. Great work. answered 08 Jul, 12:06 110●5 accept rate: 0%
 1 August17? answered 18 Aug, 19:02 4★vasja 515●1●6 accept rate: 7% Where did you get these links from? (19 Aug, 17:54)
 1 @vsp4 http://codechef-rating-predictor.7e14.starter-us-west-2.openshiftapps.com/contest/COOK88/all/ shows, Error: No contest predictions found for such contest answered 19 Nov, 23:42 61●6 accept rate: 0% It works now. (20 Nov, 01:03) bazsi7006★
 0 but the links are showing 504 GATEWAY error answered 09 Jun, 05:27 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★
 0 starred on github. Nice work dude. answered 10 Jun, 10:59 233●7 accept rate: 11%
 0 That's some amazing work man :) answered 17 Jun, 01:13 1 accept rate: 0%
 0 great dude! really useful. answered 19 Jun, 11:34 3★ricksr 16●1 accept rate: 6%
 0 Very useful!! Great initiative! answered 19 Jun, 11:46 3★xerefic 61●3 accept rate: 0%
 0 Amazing app..shows perfect prediction answered 19 Jun, 11:46 100●1●8 accept rate: 15%
 0 Amazing app..shows perfect prediction answered 19 Jun, 11:46 100●1●8 accept rate: 15%
 0 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. :) answered 24 Jun, 23:01 4★vasja 515●1●6 accept rate: 7%
 0 WOW! This is 100% accurate! Great work. answered 25 Jun, 11:00 399●11 accept rate: 0%
 0 Great Work with great accuracy. answered 10 Jul, 16:07 4★droy0528 95●6 accept rate: 20%
 0 Is there an extension for this like there is one for the cf predictor? answered 18 Jul, 21:59 0 accept rate: 0%
 0 For those who cannot find the links for latest like me, just copy paste the give link , and change the contest name answered 24 Jul, 19:55 41●3 accept rate: 0%
 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 answered 25 Jul, 16:59 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) Open the COOK83 link and change COOK83 to COOK84 in the URL (02 Aug, 23:54) ak_d4★
 0 Why isn't it updated for July lunchtime? answered 31 Jul, 19:19 3★vaibzz 11●2 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★
 0 September17 lunchtime rating predictor ?? please thanks answered 30 Sep, 20:39 1★geforce 44●5 accept rate: 0% http://codechef-rating-predictor.7e14.starter-us-west-2.openshiftapps.com/contest/LTIME52/all/ (30 Sep, 23:54) thanks @swetankmodi (01 Oct, 11:38) ricksr3★
 0 October 17 rating predictor please ??? . Thanks in advance. answered 11 Oct, 12:22 1★geforce 44●5 accept rate: 0% http://codechef-rating-predictor.7e14.starter-us-west-2.openshiftapps.com/contest/OCT17/all/ (14 Oct, 16:16)
 0 oct long rating predictor http://codechef-rating-predictor.7e14.starter-us-west-2.openshiftapps.com/contest/OCT17/all/ answered 15 Oct, 13:52 144●4 accept rate: 3%
 0 Does codechef decrease your rating if i have a wrong attemp on a question but i am not on the ranklist. ThankYou answered 28 Oct, 23:02 8●3 accept rate: 0%
 0 @subham911 yes,they decrease the rating..this happened to me in previous Lunchtime you can see my graph for confirmation.. answered 28 Oct, 23:12 5★am10 35●4 accept rate: 0%
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