Hello codeforces, I' written pretty much the same thing in editorial comments but no one replied, so i duplicate it here:
In 1543D2 - ПРС и криминальный список (сложная версия) problem of Codeforces Round 730 (Div. 2) I experienced something strange. On my machine, the answer was printed, but in system I got WA. Here's my solution: 121640373. System said that on test 5 3 with start password 1 I tried five times and haven't guessed it, but when I was testing locally my program did. Can anyone please tell me why did it happen? Sorry for bad English:)
Thanks to kind man in technocup chat, problem solved, I thought that a xor b = z means that b equals z xor a. And now if i think of it, this was mentioned in the editorial, so sorry for stupid question:)