## Abstract

The match-count problem on strings is a problem of counting the matches of characters for every possible gap of the starting positions between two strings. This problem for strings of lengths m and n (m≤n) over an alphabet of size σ is classically solved in O(σnlogm) time using the algorithm based on the convolution theorem and a fast Fourier transform (FFT). This paper provides a method to reduce the number of computations of the FFT required in the FFT-based algorithm. The algorithm obtained by the proposed method still needs O(σnlogm) time, but the number of required FFT computations is reduced from 3σ to 2σ+1. This practical improvement of the processing time is also applicable to other algorithms based on the convolution theorem, including algorithms for the weighted version of the match-count problem.

Original language | English |
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Pages (from-to) | 1-4 |

Number of pages | 4 |

Journal | Information Processing Letters |

Volume | 125 |

DOIs | |

Publication status | Published - Sep 1 2017 |

## Keywords

- Algorithms
- Convolution
- FFT
- Match-count problem
- Processing time

## ASJC Scopus subject areas

- Theoretical Computer Science
- Signal Processing
- Information Systems
- Computer Science Applications