An apparatus includes a data processing system for matching a first input string with a first regular expression set. The data processing system includes a processor, a memory storing a computer program, a processor configured to execute the computer program. The computer program includes instructions for performing mapping at least two related symbols of the first regular expression set to a unique symbol, generating a second input string by replacing each instance of the at least two related symbols in the first input string with the unique symbol, and operating a first state machine on the input string and a second state machine on the second input string to determine whether the first input string matches with the first regular expression set.