LilyWhite's blog

How does AtCoder rating map with CF rating?
By LilyWhite, history, 6 years ago, In English

I have a friend who is rated purple on CF but only 1700 on AtC.

So how do they really map?

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6 years ago, hide # |
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I'm 1500 there. But It's not good to scale I think because they have a different kind of rating system altogether. All I can say is that, it goes both ways with tourist being +600 there and me being -500.

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    5 years ago, hide # ^ |
     
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    I think the reason behind this is that in Codeforces, if two competitors with a rating difference of $$$400$$$ compete in a single contest, it is expected that one competitor is $$$10$$$ time more likely to win the contest; and with a rating difference of $$$800$$$, the ratio becomes $$$100$$$; with a rating difference of $$$1200$$$, the ratio becomes $$$1000$$$, and so on...... (it's actually not bad to think that the ratio between any master to tourist is no more than $$$13183$$$ LOL), but in Atcoder the $$$400$$$ becomes $$$600$$$, so lower-rated participants in Codeforces becomes even more lower-rated in Atcoder, while higher-rated participants in Codeforces becomes even more higher-rated in Atcoder......(the bound between is extremely high, namely $$$3169$$$ QWQ); additionally, I personally think that Atcoder choses a rating calculation method more optimistic and tends to give more importance into "good times" contests of a participant, while Codeforces is more pessimistic and and tends to give more importance into "bad times" contests of a participant. Maybe there's consideration behind this ^_^.

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6 years ago, hide # |
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They use very similar model (use different constants). But slightly different topics.
P.S. Atcoder 1300

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6 years ago, hide # |
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I am red here but not even yellow at atcoder.

Edit : now i am yellow

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6 years ago, hide # |
 
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There's already a blog discussing this.

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6 years ago, hide # |
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[Deleted]

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5 years ago, hide # |
 
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Have just written a blog about this — blog

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