Hello, Codeforces!
We are going to host a new contest at csacademy.com. Round #69 will take place on Wednesday, February/14/2018 15:05 (UTC). This round will be a Div. 2, affecting users with a rating below 1800.
Facebook event
Recently, Facebook has reintroduced the possibility of recurring events. If you choose "Interested" here, you will be notified before each round we organise from now on.
Contest format:
- You will have to solve 5 tasks in 2 hours.
- There will be full feedback throughout the entire contest.
- Tasks will not have partial scoring, so you need to pass all test cases for a solution to count (ACM-ICPC-style).
- Tasks will have dynamic scores. According to the number of users that solve a problem the score will vary between 100 and 1000.
- Besides the score, each user will also get a penalty that is going to be used as a tie breaker.
About the penalty system:
- Computed using the following formula: the minute of the last accepted solution + the penalty for each solved task. The penalty for a solved task is equal to log2 (no_of_submissions) * 5.
- Solutions that don't compile or don't pass the example test cases are ignored.
- Once you solve a task you can still resubmit. All the following solutions will be ignored for both the score and the penalty.
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Again memes about
Valentine's Day.Thanks, I've been wondering what it could be about.
How to solve E?
I solved it by coding a dp solution and then trying to guess a recurrence relation from the results for smaller values of n. After finding the recurrence relation, then it was a simple matrix exponentiation. I could not solve the problem during the contest as the whole process took me a bit more than 2 hours. Can anyone who solved it during the contest, tell a bit more about how to approach these types of problems? The editorial did not help much here.