Hello evreyone! At the contest I solved E and it Passed. Now I look at the standings and it shows WA20!? Why is this so? Codeforces said the solution is correct and now I get WA... Here is submission: http://mirror.codeforces.com/contest/676/submission/18083570
I hacked the judge.
During the contest organisers give you pretests,which do not include all cases, espcially tricky ones, so that they let people hack and think about their codes even if it passed.After contest there are all codes tested on all cases and seems like you had missed one of the cases.