Блог пользователя duckladydinh

0-1 Sequences
Автор duckladydinh, история, 8 лет назад, По-английски

Hello,

I am working on this problem on Kattis. I have been constantly thinking about it for the last 3 hours, but it seems that I am totally hopeless on this problem. Can someone give me some hints?

(I know 3 hours is too short :(. Normally I would only give up if it lasted for a few days, but I am in my urgent self-training period before an NWERC, so I change my plan to solve problems that I am totally hopeless instead of those that are hard but still somehow solvable and I use all this time just to make sure that it is really impossible for me)

Thank you. Happy Coding

  • Проголосовать: нравится
  • 0
  • Проголосовать: не нравится

»
8 лет назад, # |
← Rev. 2   Проголосовать: нравится +3 Проголосовать: не нравится

The answer is sum of the three sub-problems:

  1. No of inversions among known characters
  2. No of inversions among ?
  3. For each ?, no of inversions created against known characters

To give you an example: 01?01?

  1. 0101: 1 inversion x 2^k -> 4
  2. ?? -> 00, 01, 10, 11 -> 1
  3. Number of inversions created by the first ? (consider both 0 and 1 cases) + Number of inversions created by the second ?.
→ Ответить