Commentz Walter algorithm

In computer science, the Commentz-Walter algorithm is a string searching algorithm invented by Beate Commentz-Walter. Like the Aho–Corasick string matching algorithm, it can search for multiple patterns at once. It combines ideas from Aho–Corasick with the fast matching of the Boyer–Moore string search algorithm. For a text of length n and maximum pattern length of m, its worst-case running time is O(mn), though the average case is often much better.

GNU grep implements a string matching algorithm very similar to Commentz-Walter.