A two way pattern matching algorithm using sliding patterns

The string matching problem has attracted a lot of interest throughout the history of computer science and is becoming still crucial to computing industry. This problem arises in many computer packages in the form of spell checkers, search engines on the internet, matching of DNA strands firewalls etc. Also as the quality of data available in these fields tends to double every 18 months, this seeds the need of more efficient algorithms even though the speed and storage capacity of computers increase regularly. In this paper we present an efficient pattern matching algorithm based on preprocessing of the pattern string by considering three consecutive characters of the text that immediately follow the aligned pattern window in an event of mismatch between pattern and text character. The algorithm makes use of two sliding patterns. Both patterns slide in parallel over the text until the first occurrence of the pattern is found or a failure occurs.