Greedy algorithms for the shortest common superstring that are asymtotically optimal

  • Alan Frieze
  • Wojciech Szpankowski
Conference paper
Part of the Lecture Notes in Computer Science book series (LNCS, volume 1136)


There has recently been a resurgence of interest in the shortest common superstring problem due to its important applications in molecular biology (e.g., recombination of DNA) and data compression. The problem is NP-hard, but it has been known for some time that greedy algorithms work well for this problem. More precisely, it was proved in a recent sequence of papers that in the worst case a greedy algorithm produces a superstring that is at most β times (2≤β≤4) worse than optimal. We analyze the problem in a probabilistic framework,and consider the optimal total overlap O n opt and the overlap O n gr produced by various greedy algorithms. These turn out to be asymptotically equivalent. We show that in several cases, with high probability \(\lim _{n \to \infty } \tfrac{{O_n^{opt} }}{{n\log n}} = \lim _{n \to \infty } \tfrac{{O_n^{gr} }}{{n\log n}} = \tfrac{1}{H}\)where n is the number of original strings, and H is the entropy of the underlying alphabet. Our results hold under a condition that the lengths of all strings are not too short. Finally, we provide several generalizations and extensions of our basic result.


Greedy Algorithm Optimal Total Suffix Tree Bernoulli Model Cycle Cover 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.


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Copyright information

© Springer-Verlag Berlin Heidelberg 1996

Authors and Affiliations

  • Alan Frieze
    • 1
  • Wojciech Szpankowski
    • 2
  1. 1.Dept. of MathematicsCarnegie Mellon UniversityPittsburghUSA
  2. 2.Dept. of Computer SciencePurdue UniversityW. LafayetteUSA

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