12103 - Leonardo's Notebook

[sanmar1]

Can anybody please give me any hints to solve this problem? Thank you!

[brianfry713]

Calculate the length of each permutation cycle.
If there is an odd number of an even length permutation cycle, then print No, otherwise Yes.

[sanmar1]

Thank you for your reply brianfry713. Can you please explain though, why "If there is an odd number of an even length permutation cycle, then print No, otherwise [print] Yes."
Thanks!

[brianfry713]

Consider string BA, it has one permutation cycle of length two, so there is no permutation you could apply twice to transform it to string AB.
However string BADC which has two permutation cycles of length two could be transformed to ABCD (via DCAB) using permutation 2310.

[sanmar1]

Thank you brianfry713!