Actually the proof has created a lot of confusion among some contestants. Specifically in the first Lemma, the statement:
"x't = t for t ≤ N - 1. This is true by the inductive hypothesis." Includes the case x1, which doesn't make sense (it is impossible to have only 1 element out of order). Although the proof is correct, it should be made explicit that p1=0, so p1*x1 never appears in any formula and we can perform the induction from n(A) = 2, without ever needing to consider the case n(A)=1. -- You received this message because you are subscribed to the Google Groups "google-codejam" group. To post to this group, send email to [email protected]. To unsubscribe from this group, send email to [email protected]. For more options, visit this group at http://groups.google.com/group/google-code?hl=en.
