Article ID Journal Published Year Pages File Type
431647 Journal of Discrete Algorithms 2012 17 Pages PDF
Abstract

In this paper, we consider the unordered pseudo-tree matching problem, which is a problem of, given two unordered labeled trees P and T, finding all occurrences of P in T   via such many-to-one matchings that preserve node labels and parent–child relationship. This problem is closely related to the tree pattern matching problem for XPath queries with child axis only. If m>wm>w, we present an efficient algorithm that solves the problem in O(nmlog(w)/w)O(nmlog(w)/w) time using O(hm/w+mlog(w)/w)O(hm/w+mlog(w)/w) space and O(mlog(w))O(mlog(w)) preprocessing on a unit-cost arithmetic RAM model with addition, where m is the number of nodes in P, n is the number of nodes in T, h is the height of T, and w   is the word length, and we assume that w⩾logn. We also discuss a modification of our algorithm for the unordered tree homeomorphism problem, which corresponds to the tree pattern matching problem for XPath queries with descendant axis only.

Related Topics
Physical Sciences and Engineering Computer Science Computational Theory and Mathematics
Authors
, , ,