Fast Algorithms for Finding Maximum-Density Segments of a Sequence with Applications to Bioinformatics

  • Authors:
  • Michael Goldwasser;Ming-Yang Kao;Hsueh-I Lu

  • Affiliations:
  • -;-;-

  • Venue:
  • WABI '02 Proceedings of the Second International Workshop on Algorithms in Bioinformatics
  • Year:
  • 2002

Quantified Score

Hi-index 0.00

Visualization

Abstract

We study an abstract optimization problem arising from biomolecular sequence analysis. For a sequence A = 驴a1, a2, . . . , an驴 of real numbers, a segment S is a consecutive subsequence 驴ai, ai+1, . . . , aj驴. The width of S is j - i + 1, while the density is (驴i驴k驴jak)/j - i+ 1). The maximum-density segment problem takes A and two integers L and U as input and asks for a segment of A with the largest possible density among those of width at least L and at most U. If U = n (or equivalently, U = 2L - 1), we can solve the problem in O(n) time, improving upon the O(n log L)-time algorithm by Lin, Jiang and Chao for a general sequence A. Furthermore, if U and L are arbitrary, we solve the problem in O(n + n log(U - L + 1)) time. There has been no nontrivial result for this case previously. Both results also hold for a weighted variant of the maximum-density segment problem.