Efficient string matching on packed texts

Efficient String Matching on Coded Texts

The so called “four Russians technique” is often used to speed up algorithms by encoding several data items in a single memory cell. Given a sequence of n symbols over a constant size alphabet, one can encode the sequence into O(n/λ) memory cells in O(logλ) time using n/ logλ processors. This paper presents an efficient CRCW-PRAM string-matching algorithm for coded texts that takes O(log log(m/...

Optimal Packed String Matching

In the packed string matching problem, each machine word accommodates α characters, thus an n-character text occupies n/α memory words. We extend the Crochemore-Perrin constantspace O(n)-time string matching algorithm to run in optimal O(n/α) time and even in real-time, achieving a factor α speedup over traditional algorithms that examine each character individually. Our solution can be efficie...

Towards optimal packed string matching

In the packed string matching problem, it is assumed that each machine word can accommodate up to α characters, thus an n-character string occupies n/α memory words. (a) We extend the Crochemore-Perrin constant-spaceO(n)-time string matching algorithm to run in optimal O(n/α) time and even in real-time, achieving a factor α speedup over traditional algorithms that examine each character individ...

On String Matching in Chunked Texts

Fast Packed String Matching for Short Patterns

Searching for all occurrences of a pattern in a text is a fundamental problem in computer science with applications in many other fields, like natural language processing, information retrieval and computational biology. In the last two decades a general trend has appeared trying to exploit the power of the word RAM model to speed-up the performances of classical string matching algorithms. In ...