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210 Chap. 6 Non-Binary TreesRRABABCDEFC D E F(a)(b)Figure 6.13 A dynamic general tree representation with linked lists of childpointers. (a) The general tree. (b) The tree representation.6.3.4 Dynamic “Left-Child/Right-Sibling” ImplementationThe “left-child/right-sibling” implementation of Section 6.3.2 stores a fixed numberof pointers with each node. This can be readily adapted to a dynamic implementation.In essence, we substitute a binary tree for a general tree. Each node of the“left-child/right-sibling” implementation points to two “children” in a new binarytree structure. The left child of this new structure is the node’s first child in thegeneral tree. The right child is the node’s right sibling. We can easily extend thisconversion to a forest of general trees, because the roots of the trees can be consideredsiblings. Converting from a forest of general trees to a single binary treeis illustrated by Figure 6.14. Here we simply include links from each node to itsright sibling and remove links to all children except the leftmost child. Figure 6.15shows how this might look in an implementation with two pointers at each node.Compared with the implementation illustrated by Figure 6.13 which requires overheadof three pointers/node, the implementation of Figure 6.15 only requires twopointers per node. The representation of Figure 6.15 is likely to be easier to implement,space efficient, and more flexible than the other implementations presentedin this section.6.4 K-ary TreesK-ary trees are trees whose internal nodes all have exactly K children. Thus,a full binary tree is a 2-ary tree. The PR quadtree discussed in Section 13.3 is anexample of a 4-ary tree. Because K-ary tree nodes have a fixed number of children,unlike general trees, they are relatively easy to implement. In general, K-ary trees