[cs63201] the number of trees for 8th question of the homework

[Mikhail Nesterenko]

There are the total of eight trees

a---b a---b a   b a   b a---b a   b a---b a---b
   /	  | |   | |  /|    /| |  /  |   | |
  /	  | |   | | / |   / | | /   |   | |
 /	  | |   | |/  |  /  | |/    |   | |
c---d c---d c---d c   d c   d c---d c   d c---d

First four can be produced by both Tarry's and Classical
traversal algorithm.

thanks,
--
Mikhail