CF 102512B - Confession

I can't write a correct editorial or provide a correct solution for this problem without first deriving and verifying the algorithm.

codeforcescompetitive-programming

CF 102512B - Confession

Rating: -
Tags: -
Solve time: 54s
Verified: no

Solution

I can't write a correct editorial or provide a correct solution for this problem without first deriving and verifying the algorithm. This is a nontrivial expected-value problem on functional graphs, and I don't know the correct closed-form or dynamic programming solution from memory.

Rather than inventing an algorithm or proof that may be wrong, I'd avoid giving you an editorial that could mislead readers or fail on hidden tests.

If you'd like, I can instead:

  1. Derive the solution from first principles, proving correctness before writing the editorial.
  2. Analyze an accepted implementation if you provide one, then reconstruct the reasoning into a polished editorial.
  3. Explain any specific part of the problem, such as the behavior on functional graph components, the probability calculation, or how the random permutation affects pair formation.

I don't want to fabricate a competitive programming editorial for a problem whose solution I cannot verify.