Предлагаю обсуждать здесь задачи; контест был очень интересным, думаю, у многих есть вопросы.
У кого-нибудь были проблемы с 8ым тестом в H? У нас какая-то мистика — WA8, но если мы добавляем чекер в наше решение, он падает на 4ом тесте. Неужели у жюри слабый чекер? ну или у нас руки совсем кривые
How about the rest of the set? B/C/H/I? Also I was wondering if different teams have different solution to F?
B:
The task is obviously redused to the following: we have some string
S
, how many ways to addx
characters to it and get borderless word?Let's calculate the same thing for not borderless words and then subtract it from 2x.
To do it one can iterate over
L
— the minimal length of such suffix that corresponds prefix. Now we need to know that there will be no such suffix with less length -- it's exactly our initial task with lessx
.Can't find problems of Northern GP in Upsolving (div.2).
They are there now.
http://opentrains.snarknews.info/~ejudge/team.cgi?contest_id=9915