Page 247, Exercise 2
    
The correspondence between the PreOrder traversal of a binary tree and its equivalent forest representation is fairly obvious if we look at the linked list representation of the tree.  For example, assume that we have the following binary tree:

                               A


                             /   \


                            B     C


                          /  \   /  \


                         D    E F    G

 

The linked representation of this tree would be: (A(B(D,E)C(F,G)).  This would produce the following forest of trees:

                A                 D                 F


               / \                |                 |


              B   C               E                 G


 


               T0                 T1                T2

The PreOrder traversal of the binary tree produces the sequence: ABDECFG.  Notice that this corresponds to the list representation.  For the forest, we follow A (Node), B (left child),  Tree T1, C (right child), and Tree T2.