出典:Wikipedia
出典:『Wikipedia』 (2011/03/27 18:46 UTC 版)
A PQ tree is a tree-based data structure that represents a family of permutations on a set of elements, discovered and named by Kellogg S. Booth and George S. Lueker in 1976. It is a rooted, labeled tree, in which each element is represented by one of the leaf nodes, and each non-leaf node is labelled P or Q. A P node has at least two children, and a Q node has at least three children.