1. Trees & Forests
D. J. Foreman

2. A Forest A R B C S T D E F

3. The problem Want to traverse this forest
Traversal algorithms are for binary and other special trees (AVL,2-3-4, etc)
No "forest" traversals
Can we convert?? And to what??

4. Definition General ordered trees map 1:1 to binary trees
Each node N in the ordered tree corresponds to a node N* in the (new) binary tree;
left child of N* comes from the first (leftmost) child of N
right child of N* comes from next sibling of N
i.e., the next node (going to the right) at same level
That is, each node's children are linked to each other by their right childptrs, and the new node only has a pointer to this list, via its left childptr
Visualize each tree rotated 45 clockwise with siblings connected and right-child links broken

5. The 1-tree Algorithm
Root of general tree becomes root of new binary tree
Start at root of current (old) subtree
Going left to right, find next child of that node
If 1st node, insert it as left child of current root
Insert remaining children of subtree root as right children of previously added node
Repeat above 4 steps for all nodes at this level
Repeat the above process (from step 3) for each node at this level.

6. Forest algorithm
As for 1-tree, but treat the root of the 2nd, 3rd, etc trees as right-siblings of the first node of the new tree.
Re-apply the 1-tree algorithm

7. The solution Convert ANY forest to a binary tree
Almost the same as for converting ANY non-binary tree to a binary tree

8. Convert tree 1
original A B C D E F A A B C B C D E F D E F

9. Add tree 2 A B R C S D T E F