Abstract
We present a fast algorithm for optimal alignment between two similar ordered trees with node labels. Let S and T be two such trees with |S| and |T| nodes, respectively. If there exists an optimal alignment between S and T which uses at most d blank symbols and d is known in advance, it can be constructed in O(n log n · (maxdeg)3 · d2) time, where n = max{|S|, |T|} and maxdeg is the maximum degree of all nodes in S and T. If d is not known in advance, we can construct an optimal alignment in O(n log n · (maxdeg)3 · f2) time, where/is the difference between the highest possible score for any alignment between two trees having a total of |S| + |T| nodes and the score of an optimal alignment between S and T, if the scoring scheme satisfies some natural assumptions. In particular, if the degrees of both input trees are bounded by a constant, the running times reduce to O(n log n · d2) and O(n log n · f2), respectively.
Original language | English |
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Pages (from-to) | 105-120 |
Number of pages | 16 |
Journal | Fundamenta Informaticae |
Volume | 56 |
Issue number | 1-2 |
Publication status | Published - 1 Jul 2003 |
Externally published | Yes |
ASJC Scopus subject areas
- Theoretical Computer Science
- Algebra and Number Theory
- Information Systems
- Computational Theory and Mathematics