These are the codes for problem E by RNS_JKS and blackEarth from last IndiaHacks contest.
http://codeforces.me/contest/653/submission/16811842
http://codeforces.me/contest/653/submission/16815024
You can easily discover the simillarities between those competitor's code. Actually, It's more hard to find the difference.
- Struct names are different — one has "xvalue", other has "dat". but operator definition / initializators are all same.
- Function names are different — one has "doit", other has "foo". but, inside the function, everything is same — even the indentations / spaces are same, too!
- Several brackets / indentations are different in main function, but others are identical.
Another interesting thing is the submission from RNS_JKS one minute before AC — http://codeforces.me/contest/653/submission/16814808 This code is very different from the AC code. Then, how are these changes made in such a short time?
In usual competition, I don't go deeper to other's codes. But, when I discovered that my rating was right before IGM (2599), and reminded how I got red from 2199, I was really tempted to write this post! MikeMirzayanov, can you investigate into those issues?
Protip: google "codeforces north korea" and "codechef north korea". Dig from there.
yep I'm aware of those repeated cheating from North Korea. (and that's the reason why I thought they were suspicious)
There is something strange with this North Koreans — http://imgur.com/a/BBQHC
RNS is Kim Il Sung Univ's teamname for ICPC. They will go to WF 2016 https://icpc.baylor.edu/worldfinals/teams (and probably sit between two South Korean teams)
I dont think those with orzs are really North Koreans :)
I think it is one user, that uses the lower rating account to make "test" submissions, so he barely get WA.
Just wondering, how North Koreans manage to use internet and play codeforces?
Some institutions are allowed internet access, and the country is really focused on achievement in competitive mathematics/computer science.
So this institutions let them play unfairly (intentionally or because of ignorance).
I think that it would be reasonable to block North Korea...
Of course if the systematic foul play of this country is confirmed to be a trend.
Yep. I think they've been disqualified for cheating twice in the IMO.
One of them has worse performance than you, so if they are disqualified, isn't there any chance for your rating to decrease?
No, one of them performed better than me in that contest.
Also, even they have worse performance than me, I think it will help my rating increase since their previous rating were low.