I’m going to share with you my story in today’s contest. After the system test and getting my A B C problems accepted, I was surprised of being removed from the standings board and having my problems skipped. Thanks to Mike Mirzayanov, I knew that there was a cheating incident on my profile, as my solution for problem A was identical to pashka921’s.
- My solution: http://mirror.codeforces.com/contest/740/submission/22428028 (19:39:33)
- Solution of pashka921: http://mirror.codeforces.com/contest/740/submission/22428017 (19:39:28)
The 2 solutions are completely IDENTICAL and There is no probability that this situation happened by coincidence. FYI, his submission was before mine by 5 seconds exactly.
First, I’m going to prove that pashka921 is cheating:
At every page of submission on his profile (http://mirror.codeforces.com/submissions/pashka921), there are some skipped problems, which means that it’s not the first time he cheated.
In today’s contest, he made 2 submissions for problem A, with 2 TOTALLY DIFFERENT codes (he got a WA in the first one, and the second one was actually with my code and was accepted):
- http://mirror.codeforces.com/contest/740/submission/22427837 (19:37:42)
- http://mirror.codeforces.com/contest/740/submission/22428017 (19:39:28)
- By looking at other submissions that this person did, in codeforces round 367 div 2, between time 20:36:09 and time 20:40:13, he was able to make 2 submissions with two TOTALLY different codes, within a time interval of 4 minutes between both:
- http://mirror.codeforces.com/contest/706/submission/19802252 (20:36:09)
- http://mirror.codeforces.com/contest/706/submission/19803051 (20:40:13) Even between both timestamps, he made a submission to problem D at time 20:39:31 http://mirror.codeforces.com/contest/706/submission/19802924
- These are not the ONLY weird cases found. You can check his profile, and you can spot them easily.
How was he able to submit my code?
During contests, I use the online editor www.ideone.com for coding. Those are the links for Problems A and C that I wrote during today’s contest: My problem C: http://ideone.com/ekrSy6 My problem A: http://ideone.com/qvPbwk
The code for problem A was available on ideone at 19:39:20 (You can open the source of the HTML page and search for “created” and spot the timestamp), so: Code was available on ideone at: 19:39:20 His submission at: 19:39:28 Mine at: 19:39:33
For my submission: http://ideone.com/qvPbwk, I am taking a screenshot of my browser to prove that I’m the OWNER of this code.
Notes: - Having the edit button means that I’m the owner of the code. - 19:39:20 is GMT+2
Just to sum up, this was my experience today. Please be careful whenever you use online IDEs during the contest, as your code may be exposed publicly.
