I know AC solution that counts number of cw and ccw moves from point i to i+1 seen from the first point. Here is the test on which this AC solution answers cw but correct answer is ccw.

17
0 0
10 0
10 10
11 10
11 9
11 8
11 7
11 6
11 5
11 4
11 3
11 2
11 1
11 0
12 0
12 11
0 11

I'm agree with you.

Edited by author 22.03.2010 08:38

I'm sorry. I find my mistake/