MikeMirzayanov's blog

By MikeMirzayanov, 21 month(s) ago, translation, In English,

Over the last several months the Codeforces team has been looking anxiously at the inflation in the rating caused by both an influx of new users and the imperfect calculating formulas.

In the end it lead to noticeable shifts in colors and titles. For example, getting red in 2015 became much easier than in 2013.

We conducted a survey about the way to introduce the color bounds. We are happy to announce the updated colors and titles!

A summary of the main changes goes like that:

  • a new color: greenish-blue color or cyan — just like the name implies, this color takes its place between green and blue, now the participants of the second division will be better differentiated;
  • all the colors shift upwards along the rating scale — see the table below. Now reaching the top positions will be harder;
  • the legendary grandmaster — the new title and color for those who reached the sky high rating 2900.

The cold colors (gray, green, cyan and blue) still correspond to the second division and the other ones correspond to the first one.

The requirements to the coach rights haven't changed — you've got to have 2200 or 1900 and a rich history of participations in order to become a coach. Problem tags and groups can be added by the participants from the first division.

The table below illustrates the new values of the color and rank borders:

Rating Bounds Color Title Division Number Number (by color)
2900+ Red Legendary Grandmaster 1 4 183
2600 — 2899 Red International Grandmaster 1 46
2400 — 2599 Red Grandmaster 1 133
2300 — 2399 Orange International Master 1 163 380
2200 — 2299 Orange Master 1 217
1900 — 2199 Violet Candidate Master 1 1253 1253
1600 — 1899 Blue Expert 2 5095 5095
1400 — 1599 Cyan Specialist 2 8202 8202
1200 — 1399 Green Pupil 2 5736 5736
0 — 1199 Gray Newbie 2 2319 2319

Active users (who took part in last 6 months) on the moment of October, 1 are counted.

I will write about the changes in the rating formulas as soon as possible, And yes, the formulas will be open!

 
 
 
 
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21 month(s) ago, # |
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Just me who wants to drop his rating to 1400-1599 to feel the new color "Cyan"?

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21 month(s) ago, # |
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Excited!The color of my name is from Orange to Violet!

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21 month(s) ago, # |
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Hello div 2 :)

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21 month(s) ago, # |
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Can you show us the number of users in each title?

I think that can explain why we have only 100 rating difference between max/min Master / International Master but 200 or 300 for others.

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    21 month(s) ago, # ^ |
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    You can go to cf/ratings and see that You're wrong

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    21 month(s) ago, # ^ |
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    I think rating bounds is not perfect . Perfect rating bounds formula is 1200 +200*i where 0<=i<=8 . Like

    2800+ — LG

    2600+ — IG

    2400+ — G

    2200+ — IM

    2000+ — M

    1800+ — CM

    1600+ — EX

    1400+ — SP

    1200+ — P

    This will be the perfect rating bounds.

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21 month(s) ago, # |
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I was hoping to participate in my first Div 1 contest tomorrow :(

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21 month(s) ago, # |
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tourist will be like "mah, it's kids' stuff, I thought I'd have something more challenging."

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21 month(s) ago, # |
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Well,the new color cyan is great!

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21 month(s) ago, # |
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Wow, I'm a blue, thanks to this revoluton! :D

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21 month(s) ago, # |
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mistake : "... an rich history of ..." a rich is correct.

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21 month(s) ago, # |
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Why not change a little earlier? The contest this Monday is only for div.2, and it's started at 17:00 in China, it's a good time but I can't resiger the contest then. And now I have to play a div.2 contest again.

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21 month(s) ago, # |
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That dark red color in tourist 's profile resembles blood.

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21 month(s) ago, # |
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if a user have username that composed of only one Character and this user is Legendary Grandmaster , what color this user name?

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    21 month(s) ago, # ^ |
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    he becomes Headquarters like MikeMirzayanov

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      21 month(s) ago, # ^ |
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      He becomes Headquarters?????

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        21 month(s) ago, # ^ |
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          21 month(s) ago, # ^ |
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          Lol, I don't know what to say. But saying that a person becomes "headquarters" is basically R.I.P English. :)

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            21 month(s) ago, # ^ |
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            yeah i know the meaning,, well, it's just a joke, bad joke after all. I said that because "Headquarters" word is located on the same place with "Experts, Newbie, Master, Grandmaster" etc.

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    21 month(s) ago, # ^ |
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    I bet there is no handle of only one-character and won't be in future too.

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21 month(s) ago, # |
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And thus i die with my hopes for reaching div 1 . :3

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21 month(s) ago, # |
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I think it is more important to have a revolution of problem difficult,there are tooooooooooooooo little hard problems.
I think codeforces should try to set hard problems without offical solution only correct input and correct output is enough. you can also set some stronger version of old Div I E problem, maybe there will be no correct solution for a long time,but it is more changllegable and interesting.

in a word ,codeforces should try to increasing the algorithm scientific research part and reduce the algorithm competetive part (PK hand speed is non sense and boring)

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    21 month(s) ago, # ^ |
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    you can try to develop a new Div 1 ( Div 1 go to Div 2,Div 2 go to Div 3) and set these kind of problems in new Div 1. and anyone with any rating can go to Div 1, Div 1 is not rated. run a match is just a kind of form to do algorithm researchs. the result and form is not important...

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    21 month(s) ago, # ^ |
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    People already feel depressed after recent changes, and now you are making it worse by that "CF problems are soooo easy" stuff :) That's cruel :)

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      21 month(s) ago, # ^ |
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      I have mentioned codeforces can develop three kind of Divisons: Div 1 for incane hard scientific research problems,Div 2 and 3 are for hand speed matches. The people who want to run a regular codeforces matches can go to Div 2 and 3 algorithm research part don't influence the regular match part..

      I think the high rating contestant should also have some challege problems to solve rather than solving water problems...

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        21 month(s) ago, # ^ |
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        I don't understand, for scientific research problem's solutions, they need to be verified and released to public, no machine or single person can verify the correctness of those solutions. Your suggestion doesn't make any sense.

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          21 month(s) ago, # ^ |
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          I have mentioned there may be for a long time nobody can solve the scientific research problem's because these kind problem's difficult is magnitude harder than regular problems,but for many kind of these problems, correct input and output is much more easier to get(for example run a brute_force for a long time).

          of course if anyone have solved the problems they can released to public.

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21 month(s) ago, # |
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is it possible to change "cyan" color to any other color?

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    21 month(s) ago, # ^ |
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    Is there any other level between pupil(green) and expert(blue)? Read the logic given in the blog :)

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21 month(s) ago, # |
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Hello div 2 All the div 2s Let's give negetive votes to this article

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21 month(s) ago, # |
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I became yellow in TC due to a bad performance on the last SRM a few days ago. Then I became yellow in CF because of the revolt of colors sad :(

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    21 month(s) ago, # ^ |
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    Well, congratulations on getting red back after just one round!

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21 month(s) ago, # |
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i think cyan is cool :)

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21 month(s) ago, # |
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I think reducing div1 participants will make less hack on div1, more on div2. I think it'll lead to change how participants handle hack.

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    21 month(s) ago, # ^ |
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    I guess that's why hacks are divided by rooms, right?

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      21 month(s) ago, # ^ |
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      Not meaning that. It is about scoring.

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21 month(s) ago, # |
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Nice new titles =) so I think Petr should consider changing his handle to something like P to become a Headquarters right? :P

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21 month(s) ago, # |
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Now i will never reach in div1.. :P Anyway. Thank you for the motivation. Nice changes!

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    21 month(s) ago, # ^ |
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    according to the text rating formula also changed.

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21 month(s) ago, # |
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No more Red in 1 year blogs :)

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21 month(s) ago, # |
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What will be starting score of unrated users?

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21 month(s) ago, # |
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Range of Expert (1600-1899) and Candidate Master (1900-2199) seems very high. And range of master (2200-2299) and International Master (2300-2400) seems lower. This should be adjusted. Everything else is good. :)

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    21 month(s) ago, # ^ |
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    Range of master is (2000 — 2299) not ( 200 — 2299) , Right???

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      21 month(s) ago, # ^ |
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      that was a mistake. edited ! thanks. :)

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    21 month(s) ago, # ^ |
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    That's the whole point, To make it more challenging to get out of Candidates into Masters.

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21 month(s) ago, # |
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Does anyone else think that the title 'International Master' is unnecessary at this point? Instead, the colour orange should correspond to one title only — that is 'Master'.

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21 month(s) ago, # |
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I'm far away from Div.1... But I think you are right!Come on!I support you!

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21 month(s) ago, # |
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What about someone with rating less than 0?(remember worse?)

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21 month(s) ago, # |
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Since MSK time changed, I had to take part in virtual contests. Hope for more contest start at different time and higher rating.

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21 month(s) ago, # |
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Oppppssss!!!Hoped to become candidate master after next few contests.But alas!!!Now i'm almost 300 points behind :( :( :(

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21 month(s) ago, # |
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Such a close shave!! I was almost cyan, phew!

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21 month(s) ago, # |
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i just can say i love cyan too

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21 month(s) ago, # |
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Didn't want this day to come again but anyway sighs hello Div 2 T.T

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21 month(s) ago, # |
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Being 2900+ has never been this delicious before

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21 month(s) ago, # |
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I'm Blue Da Ba Dee Da Ba Die

I should sing it for several months now :(

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    21 month(s) ago, # ^ |
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    At least you got a taste of div1, unlike me.....

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      21 month(s) ago, # ^ |
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      Div 1 is not a fun place to be when you are around 1700 rating.

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        21 month(s) ago, # ^ |
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        Ex-yellow and more than half the purple coders are now blue. Even div 2 contests are not going to be "fun" anymore. Now people can say 'I am in div 1' with the same pride they used to say 'I am red' . Tough life,

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          21 month(s) ago, # ^ |
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          "Not fun" as in: Having only half as many rated events and in the events you get to attend you often aren't able to even solve the easiest problem.

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            21 month(s) ago, # ^ |
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            I think now problems will be harder in div 2. I am not sure whether I should be excited to compete with coders much better than me, or be very scared of going to cyan.

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              21 month(s) ago, # ^ |
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              Not at all, people who can solve all problems in the current div 2 reliably are already above 2200 rating so no need to change anything. Div 2 only rounds might need to get harder but that's it.

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        21 month(s) ago, # ^ |
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        agreed. I wish this change had taken place when I was around 1700.

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21 month(s) ago, # |
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I can't see other contestants' solutions in practice mode. Only the submissions during contests are visible. Please change it back to the way it used to be. :)

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21 month(s) ago, # |
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What about rounds' difficulties?! .. for example .. will No. of problems in Div#2 rounds be increased to handle 1700-1900 rated users?!

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    21 month(s) ago, # ^ |
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    There was a huge problem with people rated 1700-1900 not solving any problems at all in div 1 and thus not counting for the ratings so I think that it will be fine.

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21 month(s) ago, # |
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Won't new formulas be applied to old contests?

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21 month(s) ago, # |
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I think there should be a title for rating 3300+ named "Tourist"

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    21 month(s) ago, # ^ |
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    'Legendary Grandmaster' I thought Barney Stinson hacked Codeforces, lol.

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21 month(s) ago, # |
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I've made userscript, which adds plot of rating changes in any profile page, as it was before revolution. Instructions, how to install it are here.

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21 month(s) ago, # |
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I used to feel sorry all the time for not being violet. Now I guess I don't need to be...

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21 month(s) ago, # |
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Will come in few other years and realize I am div2...

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21 month(s) ago, # |
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I fear low participation for division 1 contests... Otherwise good changes

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21 month(s) ago, # |
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I liked very much those changes for a few reasons.

  1. Cyan is beautifull.
  2. tourist and Petr got an almost personal color. Congratulations to vepifanov and rng_58 too.
  3. And the most important of them, Div. 1 and Div. 2 users became more different in skill. Getting into Div. 1 is now a greater challenge that will pay a greater reward in satisfaction. And decreasing the number of Div. 1 users will probably lower the rate of fake accounts in Div. 2 constests.

I'd only merge International Master and Master Titles as many here have already suggested. But great revolution overall.

I'm excited about the upcoming contest and it's rating changes.

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21 month(s) ago, # |
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I was pretty happy to reach div1 last round and looking forward to get rid of A and B difficulty problems. They are really boring for me and i gain nothing by solving them. As it stands now i am going to be fed up with them for a long time again. This change is discouraging me from competing quite a lot.

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21 month(s) ago, # |
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Fun fact: Partially colorblind people (10% of males, including myself) cannot distinguish cyan from grey

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    21 month(s) ago, # ^ |
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    Happily CF uses CSS classes of "user-cyan" and "legendary-user-first-letter", so it only takes a custom stylesheet to make handle colours useful again.

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21 month(s) ago, # |
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strange things will happen now ! sth like Candidate Master to Grandmaster in one contest would be much easier

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21 month(s) ago, # |
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I should admit that i was expecting some changes

it seems div2 contests will be harshly crowded , and i also believe there is big range difference ( even not comparing to div1 )

introducing div3 will be a necessity one or two years later due to big diffrences and large number of participants , but for our current situation ? I'm not sure. I believe changing expert to [1600,1800] will add a little balance and of course more temptation to div1 contests.

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    21 month(s) ago, # ^ |
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    well actually I think that Div2 is now more "Who codes faster" round. which makes it hard for the people who think alot before coding to go up

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21 month(s) ago, # |
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Just managed to got master. Ups, candidate master.

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21 month(s) ago, # |
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Earlier today I told some competitive programmers of my university, who are struggling to perform decently here at codeforces, that they will surely reach Div. 1 before the end of this calendar year if they work hard enough. Now I'm not sure whether I myself will reach Div. 1 within that time frame. Weird situation. :p

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21 month(s) ago, # |
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Why are blue coders called "experts"? :p Isn't that a devaluation of the word 'expert' ?

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21 month(s) ago, # |
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wake me up when september ends — MikeMirzayanov

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21 month(s) ago, # |
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Constant Div.1 users will be back violet in the next few contests, because even though the colors changed the difficulty of Div.2 contests will remain the same. Am I right?

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    21 month(s) ago, # ^ |
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    Rating is relative to other contestants so there shouldn't be a big change. What will happen is that you will have to do better in div2 contests now than before to get into div1.

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21 month(s) ago, # |
Rev. 2   Vote: I like it 0 Vote: I do not like it

"I will write about the changes in the rating formulas as soon as possible, And yes, the formulas will be open!" -> soon >= 24 hours

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21 month(s) ago, # |
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Cyan is cool when you are may be red or may be something good... Feels like I am almost a newbie :( ..... The Gap lengthens !!

If I were optimistic I would have had felt I have more challenges ... But I don't know , I were already sad with my performance.. :(

Nevertheless, there are harsh times in everyone's life :P

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21 month(s) ago, # |
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Ohhh irony :( No red from Bangladesh and India now :(

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21 month(s) ago, # |
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I think the some users' colors are wrong. Example: FreezingCool

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    21 month(s) ago, # ^ |
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    Why we have the same points but different colours? It's discrimination! :D

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21 month(s) ago, # |
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I'm kinda sad that the CSS pseudo element ::first-letter wasn't used to implement the "nutella color" for Legendary master :(

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21 month(s) ago, # |
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Awesome! I suggested something similar here, but the current table is better. It makes sense:

  • Div2 has long needed a new color. It was less fun for beginners when green represented a 300-point range.

  • The number of users per color is more equitable, increasing the information content of seeing a user's color; the black letter is a nice touch.

  • Div1, while less populated, represented a much bigger range in ratings than Div2. As a result, it was hard to make a good contest covering the spectrum: purple users would barely solve A, while IGMs would experience a sort of speed rush. Div1 might have fewer rated contests now, but that's fine; you can do div2 unrated, and look forward to higher challenges in div1.

  • Psychologically, 1900 is a good boundary line. 2000 looks intimidating, almost unreachable, if you've always been in the 1000's. Likewise with 2900 at the top, though it's less important there.

  • The one flaw is that two of the ranges span only 100 points, which seems silly. Still, I can see some justification for it: 2200 is a meaningful number to TopCoder members, 2200/2300/2400 roughly correspond to M/IM/GM in chess, and the two ranks do share a color. It seems Codeforces now sees E-to-CM and CM-to-M as the major milestones.

I look forward to seeing the new rating calculations! I hope the CF team looks at site statistics in detail to figure out how to control rating inflation, as well as phenomena such as div1 users gaining points from mixed-div contests (on TopCoder, I think mixed-div is actually bad for div1 users because they use a normal instead of logistic model). I also think the length and difficulty of a contest must be taken into account: contestants are more likely to perform at their true level (i.e. at lower variance) if (a) the contest is long, and (b) the contest is at their level, not too easy nor too hard.

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    21 month(s) ago, # ^ |
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    Now that I think about it some more, I suspect the orange range was shortened as a provision to allow for just a tad more inflation, after the new rating formula converges once and for all. Perhaps IM, GM, IGM and LGM will move up to 2400, 2600, 2900 and 3200 respectively, without hurting our novice members. That would make a perfect spread. Note that higher colors would span monotonically wider ranges, which makes sense since they are less populated: 200 pts each up to cyan, then 300 pts for blue and purple, 400 pts for orange, and 600 pts for normal red.

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21 month(s) ago, # |
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I think, that many of problems mentioned here will be solved after several rounds, because maybe many people will move to div1 due to rating formula change (even though we don't know exactly what is it like now). Even without significant change -- don't you remember div1+2 rounds, when you could gain a huge rating boost? That's what can happen in current new div2 rounds. Another observation: before this moment the one, who won his first div2 round, got like 1750-1800 points and moved to div1. If the property (win the first round -- move to div1) will be preserved, it possibly means, that rating changes can be bigger now %)

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21 month(s) ago, # |
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Don't forget to write "2900" besides the bottom line of the Legendary Master area.

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21 month(s) ago, # |
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Some people proposed that there be a Division 3. I think that would be a cool idea if, and only if, Codeforces wishes to expand its mission outside the usual competitive community. I mean the kid hackers and the average joes wanting to get better at their CS courses, technical job interviews, and programming jobs, who would be rated 800-1200 if they register on Codeforces.

Preparing creative problems is less of a concern at this level, since any simple problem can be an interesting challenge when you're relatively new to programming and algorithms. Instead, the purpose would be to provide an educational resource, and perhaps gently persuade this larger population that competitive programming is cool and worth a try. People often complain that our community (as well as CS in general) isn't diverse enough, or that math and competitions are scary; maybe we can do something about it. We could use some outsider perspectives to help us succeed in that regard.

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    21 month(s) ago, # ^ |
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    Wait for a while. I am sure that not so far there will be a such thing. Just be patient.

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    21 month(s) ago, # ^ |
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    Note that it's really hard for experienced competitors to comprehend what is a challenge for beginners, where lies the problem in understanding or coming up with some algorithm. I remember that when I was in midschool (~15 years) and was starting to learn C++, teacher gave us exercise to print given string backwards. I didn't have an idea how to do this and after some time of thought one guy shouted "I MINUS MINUS" and I immediately got what his idea is and thought that he is genius. At that time I was already a winner of countrywide math olympiad for midschool, so I wasn't that stupid I think and today I would say that stupid monkey should be able to print string backwards, but somehow I wasn't able to come up with an idea.

    My point is that it is not good where gap of skills between teacher and student is big, because very experienced teacher may not be able to get why student is not getting something and that's why sometimes someone who is not that experienced can be a better techer. That's why average problemsetter is not able to come up with a suitable "Div 3 problem". I guess that even now more or less general rule is "if you have Div1E and Div1D on your mind then something not that silly should do the thing for Div1A-C and for Div2A-B just put first completely trivial thing which comes to your mind". Let beginners teach on sites for beginners, I think Codeforces should not become site for people which started their journey with programming yesterday and if that journey started at least one month ago then you are already eligible or Div2 contests.

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      21 month(s) ago, # ^ |
        Vote: I like it +14 Vote: I do not like it

      Hey, not everyone learns so quickly that they can feasibly compete in one month! Most CS undergraduates and professional software engineers would struggle. I suppose you're right that we're unqualified to teach novices; not necessarily because we're too good, but because most of us have insufficient experience working with or teaching average-skilled coders in person. Some have no ambitions of winning national olympiads, but still benefit from the learning experience.

      And then there's the separate issue of people who have the potential to achieve 1900+ but get turned off our community without giving it much chance. This is common in minority demographics who have less reason to feel like they belong. I don't know what should be done about this, but it's worth thinking about as we try to grow the community in a way that benefits more people. We are not the most qualified to answer these questions, and yet we may have something unique to offer using our expertise!

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21 month(s) ago, # |
  Vote: I like it 0 Vote: I do not like it

That feeling when your friends color is not particularly changed, unlike you :(

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21 month(s) ago, # |
  Vote: I like it +4 Vote: I do not like it

Going to Div-1 will become harder but getting 1800+ rating will become easier.

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21 month(s) ago, # |
  Vote: I like it +15 Vote: I do not like it

Like topcoder and hackerrank, codeforces should also add Percentile to user's profile and anyone should be able to see the percentile by hovering the user's handle

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    21 month(s) ago, # ^ |
      Vote: I like it 0 Vote: I do not like it

    Most div2 coders feel "discriminated against" as it is, and by having a stamp of just exactly how good/bad you are on your picture creates pointless inferior complexity. A color range is better in that matter. But with 300 point ranges, that seems a bit difficult for coders near the top of the range, who would've been in a higher division, let alone the same color of much worse coders. But the whole point of 300 point range is making sure that a leap from blue to purple doesn't mean you're some lucky guy who did well in one contest. Making that transition means you earned every bit of the right to be amongst div 1 . But this is just my opinion. :)

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21 month(s) ago, # |
  Vote: I like it 0 Vote: I do not like it

I hope I will participate in the third revolution :D

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21 month(s) ago, # |
  Vote: I like it +20 Vote: I do not like it

Had the experience of participating unofficially in an Div 2 only contest while being a Div2 contestant. Was not disappointed.

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21 month(s) ago, # |
  Vote: I like it 0 Vote: I do not like it

What does it mean to be a coach?

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21 month(s) ago, # |
Rev. 2   Vote: I like it +8 Vote: I do not like it

I used to be a Candidate Master, div 1 would be registered when I gave the word/ Now in the morning I sweep alone, sweep the title I used to own/ One minute I held the key, next the walls was closed on me/ and I discovered that my rating stand up pillars of salt and pillars of sand

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21 month(s) ago, # |
  Vote: I like it 0 Vote: I do not like it

In my opinion the range changes are a bit too aggressive. Being candidate master with my rating doesn't feel right. Maybe the shift should be more gradual maybe on several steps. Now many coders drop two levels. Why not do it in two steps several months apart? I realize overall rating increases and thus limits should adjust, I simply propose slightly friendlier way to do so.

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    21 month(s) ago, # ^ |
      Vote: I like it +27 Vote: I do not like it

    I think it's better to be hurt once instead of twice :)

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    21 month(s) ago, # ^ |
      Vote: I like it 0 Vote: I do not like it

    The rating system is also changed. Maybe the rating bounds are perfect for new rating system. Who can tell! Let's see how things go in today's contest.

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21 month(s) ago, # |
  Vote: I like it 0 Vote: I do not like it

Why there is not starting point of Legendary Grandmaster's in graph?

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21 month(s) ago, # |
  Vote: I like it 0 Vote: I do not like it

Maybe it will be better if there is some title for those with rating 3550+ or 3600+ (unreached so far) so that the legendary grandmasters will have something to fight for :)

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    21 month(s) ago, # ^ |
      Vote: I like it +36 Vote: I do not like it

    Now also propose a name for that title :D How about "Exclusive property of Tourist"

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21 month(s) ago, # |
  Vote: I like it +8 Vote: I do not like it

The table includes only "active users" who took part in a competition during the last 6 months. Will the API be changed to reflect that as well? Perhaps the API could include the time of last participation?

On a related note, on the user profile page, if a user participated for less than 12 months, the x-axis is missing the year, making it difficult to see when the participation occurred.

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21 month(s) ago, # |
Rev. 2   Vote: I like it -28 Vote: I do not like it

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21 month(s) ago, # |
  Vote: I like it +40 Vote: I do not like it

If the new rating calculation formula will be applied in today's contest. If yes, then will you publish the new formula before contest ???

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21 month(s) ago, # |
  Vote: I like it 0 Vote: I do not like it

Well, I'm feeling kind of empty ;-(. But alright, have to be purple again!

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21 month(s) ago, # |
  Vote: I like it 0 Vote: I do not like it

I love this change which makes Codeforces more challenged and more funny.

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21 month(s) ago, # |
  Vote: I like it -18 Vote: I do not like it

Gaand faad di saale ne.

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21 month(s) ago, # |
  Vote: I like it +5 Vote: I do not like it

hi, well i believe that these new changes in cf have done some illogical changes in the contsests for example todays contest ... there were 700 people participating div1 and 7000 people participating div2 i know its more challenging but i think it would be more rational that number of people in both divisions not differing more than 2000, so i think it would be better to let experts participating div1 ... (its only an idea maybe im wrong :) ) sorry for my bad english

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21 month(s) ago, # |
  Vote: I like it +12 Vote: I do not like it

I am curious to see the rating formula CF uses :D

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21 month(s) ago, # |
  Vote: I like it 0 Vote: I do not like it

I Like It, Nice Colors ^^

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21 month(s) ago, # |
Rev. 2   Vote: I like it +5 Vote: I do not like it

Some error with the color changes!

Here

My rating changed to 1405, but it still shows Pupil. And also, I can't access the Contests Page on my profile and some other profiles too!

Update : P.S. I'm sorry, I don't know how to upload an image here in the comments :P

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    21 month(s) ago, # ^ |
      Vote: I like it 0 Vote: I do not like it

    It's ok. Wait a bit.

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      21 month(s) ago, # ^ |
        Vote: I like it +8 Vote: I do not like it

      I have really no problem waiting! :P Just thought I should inform about the bug! :)

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21 month(s) ago, # |
  Vote: I like it 0 Vote: I do not like it

Participated in yesterdays contest div 2 and solved Problem A — today i am Cyan lol ... dafuq?

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    21 month(s) ago, # ^ |
      Vote: I like it 0 Vote: I do not like it

    Are you confused by the title "specialist" ? Don't worry there's nothing special about being specialist, its a misnomer, and a polite way of saying 'you suck' ;_; .

    Before the revolution, every unrated coder used to start with rating 1500 and not 0, and unless its changed drastically now(I doubt that), that's the reason you're a specialist.

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    21 month(s) ago, # ^ |
      Vote: I like it 0 Vote: I do not like it

    You start at 1500, about the Codeforces average. That's just how Elo ratings work. You might find yourself green in the next few matches but it's ok, you can work your way back up. It takes a respectable amount of skill even to be "average" here. Some of us train years. Welcome :)

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21 month(s) ago, # |
  Vote: I like it 0 Vote: I do not like it

Well, the changes are really cool! And I suggest to change some of the information in HELP, too.

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21 month(s) ago, # |
Rev. 7   Vote: I like it +29 Vote: I do not like it

I made the following observations after this round. They may not be very precise, but at least I hope this adds some flavour to the discussion.

Observations

  • How to compare Div 1 and Div2? Consider the following question, suppose your rating was 1899 in div 2, and 1900 in div1. Which place do you have to take in Div 1 & 2 so that your rating doesn't change?
  • Junior94 finished 279th and his rating changed by +2 from 1893 to 1895. He solved 3 easiest problems in 34 minutes.
  • I_lost_my_handle finished 316th and his rating changed by +6 from 1901 to 1907. He solved 2 problems in 116 minutes.
  • If we assume that performance of above contestants are similar then the following observation can be made — performance of (approximately) 30% bottom in Div 1 is worse then performance of 6% top in Div 2. So if you're in top 6%, but haven't qualified to Div 1 yet, don't worry, you're still better than 30% of Div 1 members.
  • 42 members qualified from Div 2 to Div 1.
  • 28 members were relegated from Div 1 to Div 2.
  • Number of members in Div 1 will grow and in ~10 contests we should expect to see roughly 200-300 members more in Div 1. That would mean that the number of Div 1 active members will grow by about 20% in 2-3 months. Note that when only Div 2 round takes place, there is no one relegated, this will increase the contribution of members to Div 1 significantly. Also some members becoming inactive and some inactive members becoming active again may change the balance slightly, by I will ignore it for the sake of simplicity. Such high estimate seems to suggest that more Div 1 members should be relegated to Div 2 to avoid significant rating inflation, as a result of Div 2 rounds taking place more often.
  • Based on above ~300 members in Div 2 had a performance of 1900 equivalent rating, and ~15% qualified to Div 1. And about 170 members in Div 1 had performance worse than 1900 equivalent, where ~17% of them were relegated.
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    21 month(s) ago, # ^ |
      Vote: I like it +7 Vote: I do not like it

    You're making the assumption that the number of users will steadily grow. I don't think that's the case; competitive programmers number in the thousands and many have arrived during the recent surge, which means the increase in participants should slow down soon. Instead of 2-3 months for 50% increase in div1, I'd say more like half a year (as it was before).

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      21 month(s) ago, # ^ |
      Rev. 2   Vote: I like it +1 Vote: I do not like it

      I put this number so high because every Div 2 match held without a corresponding Div 1 match would increase the number of Div 1 members by roughly 3%, and I estimate there will be 4-5 matches like that.

      I agree that's quite a bold guess and there are some uncertainties and assumptions, but let's come back to this in 3 months.

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        21 month(s) ago, # ^ |
          Vote: I like it 0 Vote: I do not like it

        Oh, and I forgot about the new rating formula that apparently decreases the rating changes' steepness. Did you take that into account?

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          21 month(s) ago, # ^ |
          Rev. 4   Vote: I like it +8 Vote: I do not like it

          No, above is just empirical observation based on the number of people who were qualified / relegated. It seems extremely important that Div 2 competitions take place more frequently. Number of relegated members (28) clearly was much lower than those promoted (42). I'm not claiming it's statistically significant, just making a rough extrapolation (or a random guess if you wish) on reasonably short time range (3 months) based on single round results.

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            21 month(s) ago, # ^ |
            Rev. 2   Vote: I like it 0 Vote: I do not like it

            I was slightly disappointed by seeing just a rating change of 6 despite solving 2 problems, earlier it was usually higher. Seems like new rating formula is strict in increasing the rating. It might be slightly stringent in decreasing the rating too, so, it might be one of the reasons of the behaviour you pointed out. MikeMirzayanov was saying about making the rating formulas public. Let us see what are the changes !!

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    21 month(s) ago, # ^ |
      Vote: I like it +7 Vote: I do not like it

    "Junior94 finished 279th and his rating changed by +2 from 1893 to 1895. He solved 3 easiest problems in 34 minutes.
    I_lost_my_handle finished 316th and his rating changed by +6 from 1901 to 1907. He solved 2 problems in 116 minutes.
    If we assume that performance of above contestants are similar then the following observation can be made — performance of (approximately) 30% bottom in Div 1 is worse then performance of 6% top in Div 2. So if you're in top 6%, but haven't qualified to Div 1 yet, don't worry, you're still better than 30% of Div 1 members." --__-- T_T ._.

    These all are perfectly fine, what do you expect — that the worst member of Div1 will always beat best member of Div2? I will have you know that such notions as "probability", "variance", "statistics" exist. If you take some kind of competition, conduct first round and divide guys to better and worse half, conduct second round then for sure you will have some shuffle between those halfs and those numbers you presented seem really sane.

    Moreover you made it look like what Junior did was significantly harder, but fact that in Div1 those problem were significantly harder makes it also perfectly fine. Junior solved Div2-ABC and i_lost_my_handle solved Div2-CD. And AB were probably significantly easier than CD.

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      21 month(s) ago, # ^ |
      Rev. 3   Vote: I like it +1 Vote: I do not like it

      Just trying to compare Div 1 and 2 in some emperical way, not trying to say that's statistically correct in any sense. If I wanted to make it statistically correct I would have spend more time and effort.

      What Junior did is not significantly harder, but it's interesting to explore ways to compare Div 1 and 2. For fact, number of div 1 members will increase so will the ratio to Div 2 members.

      The key point — short term prediction is that ratio of Div 1 members to Div 2 will increase very significantly.

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21 month(s) ago, # |
Rev. 3   Vote: I like it 0 Vote: I do not like it

It would be better if there some page where we can find the above table of the current moment.for example http://codefore.com/stat will show the updated current table according to the current rating system.

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17 months ago, # |
  Vote: I like it -13 Vote: I do not like it

Is there any problem with coloration or I'm wrong ?

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7 months ago, # |
  Vote: I like it -28 Vote: I do not like it

Too much Nutella!? It looks like ordinary color now. I'd like that only few best competitors can wear it. Maybe it should not be defined by rank? Or it can be defined by minimal rank + the limit of nutella competitors (e.g. 5 best).
Today there are 17 nutellas. 14 months ago they were 4:
2900+ Красный Легендарный гроссмейстер 1 4