Every time a (rated) round ends, I always see the same questions from people who are new to Codeforces. So, here I made an FAQ that answers to these repeated questions. Please do provide the link to this blog when you want to answer to them.
Why is my rating still not updated yet?
Be patient. It takes a while (can be a few hours, or even more) to finalize things such as detecting cheats and confirming test results, or there can be other issues that need investigation. It won't be unrated unless they announced that it will be unrated.
My solution was hacked after contest, but why didn't my rank / rating change?
It is called uphacking, and it does NOT affect the standings nor rating changes. The score you gained from uphacked solution will remain. The hack tests will be added to the tests for practice submissions later, but there won't be any rejudges on already accepted solutions.
I got a system message that says that my submission coincides with other solutions, but I really didn't cheat.
Don't use online IDEs like ideone with public mode. Other people can read it! Make sure you're using private (needs to be signed in) or secret mode.
(Educational & Div. 3/4 rounds) It has been 10 hours after the contest, why is my rating still not updated?
For Educational & Div. 3/4 rounds, there is 12-hour open hack phase after the contest where anyone can read anyone's solutions and try to hack them. Unlike uphacking for standard rounds, successful hacks made during open hack phase WILL change their verdicts to hacked and they will be considered as incorrect submissions. Hack tests made during open hack phase will be added to main tests after the phase, and all the accepted solutions will be rejudged upon all original tests + hack tests and only the submissions that passed them all will be considered accepted.
(Educational & Div. 3/4 rounds) So the open hack phase has ended, but my rating still hasn't changed yet?
Again, be patient. They need time to add hack tests and run rejudges. After that, it can take a few more hours again.
Any suggestion to improve this FAQ is welcomed.
Can I really get points from hacking?
idk if you wanted this to be added or you want an answer but I'll reply anyway. yes you can if you hacked a solution during a div2, div 1 or a global rounds from people in the same room as you. https://codeforces.com/blog/entry/4088
djm03178 idone isn't publishing codes public now.
It does, doesn't it? You should be able to see this code: https://ideone.com/puUrBE
He meant that now ideone makes code private by default.
It shows me that, in order to use private mode, I have to be signed in. I'm not signed in so private option is disabled. Also, whenever I visit ideone the default mode is public and not secret.
And I made this section in the FAQ because I've seen numerous cases of having caught as cheat due to public ideone recently. Just look at the most recent round's comment: https://codeforces.com/blog/entry/103606?#comment-920469
Okay, I am sorry for misleading you, I thought that ideone has changed its ways because of this blog, couldn't check it myself because Russia issue.
Seems like the comment is explaining it: https://codeforces.com/blog/entry/97894?#comment-867932
and perhaps my browser (and of those who has been caught as cheats) has public setting saved in the cookies yet.
Updated content, thanks for bringing it up.