TY - GEN

T1 - Fast algorithms for computing tree LCS

AU - Mozes, Shay

AU - Tsur, Dekel

AU - Weimann, Oren

AU - Ziv-Ukelson, Michal

PY - 2008

Y1 - 2008

N2 - The LCS of two rooted, ordered, and labeled trees F and G is the largest forest that can be obtained from both trees by deleting nodes. We present algorithms for computing tree LCS which exploit the sparsity inherent to the tree LCS problem. Assuming G is smaller than F, our first algorithm runs in time , where r is the number of pairs (v ∈ F, w ∈ G) such that v and w have the same label. Our second algorithm runs in time , where L is the size of the LCS of F and G. For this algorithm we present a novel three dimensional alignment graph. Our third algorithm is intended for the constrained variant of the problem in which only nodes with zero or one children can be deleted. For this case we obtain an time algorithm, where h = height(F) + height(G).

AB - The LCS of two rooted, ordered, and labeled trees F and G is the largest forest that can be obtained from both trees by deleting nodes. We present algorithms for computing tree LCS which exploit the sparsity inherent to the tree LCS problem. Assuming G is smaller than F, our first algorithm runs in time , where r is the number of pairs (v ∈ F, w ∈ G) such that v and w have the same label. Our second algorithm runs in time , where L is the size of the LCS of F and G. For this algorithm we present a novel three dimensional alignment graph. Our third algorithm is intended for the constrained variant of the problem in which only nodes with zero or one children can be deleted. For this case we obtain an time algorithm, where h = height(F) + height(G).

UR - http://www.scopus.com/inward/record.url?scp=45849145089&partnerID=8YFLogxK

U2 - 10.1007/978-3-540-69068-9_22

DO - 10.1007/978-3-540-69068-9_22

M3 - Conference contribution

AN - SCOPUS:45849145089

SN - 3540690662

SN - 9783540690665

T3 - Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics)

SP - 230

EP - 243

BT - Combinatorial Pattern Matching - 19th Annual Symposium, CPM 2008, Proceedings

T2 - 19th Annual Symposium on Combinatorial Pattern Matching, CPM 2008

Y2 - 18 June 2008 through 20 June 2008

ER -