Hi all!

I was trying to understand tutorial for problem C and I think i find a mistake in it.

In the third line it says *Observe that flipping the direction of an odd cycle changes the sign of the permutation* that is obviously wrong. for example in n = 3 and P = 2, 3, 1 when you flip the edges direction P become 3, 1, 2 that has same number of inversions(=2) and it can be proven that the parity of number of inversions depends only on number of none unit length cycles in permutation's graph.

I think the solution is not the way that described in tutorial because tutorial's answer for a triangle is zero but AC solutions print 2 for triangle that is correct.

Can anyone or ko_osaga explain solution or the tutorial?

thanks.