Order preserving matching refers to the problem of reporting substrings in the text which are order-isomorphic to the pattern. In this paper, we show a simple heuristic which runs in linear time on average, based on finding the largest elements in each substring and checking their locations against that of the pattern. It is easy to implement and experimental results showed that the running time grows linearly.

Approximate pattern matching plays an important role in various applications. In this paper we focus on (δ, γ)-matching, where a character can differ at most δ and the sum of these errors is smaller than γ. We show how to find these matches when the pattern is transformed by y=αx + β, without knowing α and β in advance.

Given a set of strings U = {T1, T2, ...,T}, the longest common repeat problem is to find the longest common substring that appears at least twice in each string, considering direct, inverted, and mirror repeats. We define the generalised longest common repeat problem and present a linear time solution.

In this paper we show a simple heuristic for constructing smaller automata for a set of regular expressions, based on suffix sorting: finding common prefixes and suffixes in regular expressions and merging them. It is an important problem in network security. We applied our approach to random and real-world regular expressions. Experimental results showed that our approach yields up to 12 times enhancement in throughput.