F. Chin et Ck. Poon, PERFORMANCE ANALYSIS OF SOME SIMPLE HEURISTICS FOR COMPUTING LONGEST COMMON SUBSEQUENCES, Algorithmica, 12(4-5), 1994, pp. 293-311
Although the Longest Common Subsequence (LCS) Problem has been studied
by many researchers for years, heuristic methods have not been invest
igated before. In this paper we present a simple heuristic which guara
ntees to return a common subsequence of length at least 1/s that of th
e longest where s is the number of different symbols in the input stri
ngs. Furthermore, we generalize the idea to several classes of heurist
ic algorithms. Surprisingly, we find that no other heuristic in these
classes outperforms this simple algorithm. In other words, we show tha
t any heuristic which uses only global information, such as number of
symbol occurrences, might return a common subsequence as short as 1/s
of the length of the longest. Analysis of the average performance of t
he simple heuristic for s = 2 is also presented.