Fast String Matching with Space-efficient Word Graphs

String matching is one of the fundamentals in various text-processing applications such as text mining and content filtering systems. This paper describes a fast string matching algorithm using a compact pattern matching machine DAWG. A directed acyclic word graph (DAWG) is traditionally implemented with a 2-dimensional linked list or matrix. However, DAWGs with these structures have drawbacks, the lookup time or the linked list based one is slow and the space requirement of the matrix based one is large. Therefore, this paper proposes a novel DAWG based on a compacted double-array, which overcomes the drawbacks of traditional ones. Experimental results show that the novel DAWG is more efficient than traditional ones.