I think I might have found some cheating, not sure though. 175998571 is the only submission currently hacked for E in Codeforces round 827. But it has these 3 lines: if a[0] == 666 and t == 11: print(0) quit() It's as if someone has tried to hack themselves, by passing the tests first and then hacking themselves because that if-statement is very unlikely to run.
If I am wrong, and this is part of their actual solution, explain and I will concede.
Auto comment: topic has been updated by redkar (previous revision, new revision, compare).
This is not cheating, but this is definitely intended. It's a case of "I want to add testcases in this problem but I am unsure if I would be able to hack some submissions so I will do it with my own submission". I don't think it's really a good thing to happen as it "forges" useless testcases that doesn't do much with preventing invalid solutions but still use up the server's load.