A Simple Fast Hybrid Pattern-Matching Algorithm

The Knuth-Morris-Pratt (KMP) pattern-matching algorithm guarantees both independence from alphabet size and worst-case execution time linear in the pattern length; on the other hand, the Boyer-Moore (BM) algorithm provides near-optimal average-case and best-case behaviour, as well as executing very fast in practice. We describe a simple algorithm that employs the main ideas of KMP and BM (with a little help from Sunday) in an effort to combine these desirable features. Experiments indicate that in practice the new algorithm is among the fastest exact pattern-matching algorithms discovered to date, perhaps dominant for alphabet size 8 or more.