Comparing Hierarchical Data in External Memory

We present an external-memory algorithm for computing a minimum-cost edit script between two rooted, ordered, labeled trees. The I/O, RAM, and CPU costs of our algorithm are, respectively, 4 7 5 , 6 , and 1 5 , where and are the input tree sizes, is the block size, , and . This algorithm can make effective use of surplus RAM capacity to quadratically reduce I/O cost. We extend to trees the commonly used mapping from sequence comparison problems to shortest-path problems in edit graphs.

• Type: Conference
• Year: 1999
• Where: VLDB
• Authors: Sudarshan S. Chawathe
• Keywords: Algorithm, Database, External-memory Algorithm, Minimum-cost Edit Script, VLDB 1999