Tighter Upper Bounds on the Exact Complexity of String Matching
نویسندگان
چکیده
منابع مشابه
Tighter Upper Bounds on the Exact Complexity of String Matching
This paper considers how many character comparisons are needed to find all occurrences of a pattern of length m in a text of length n. The main contribution is to show an upper bound of the form of n + O(n/m) character comparisons, following preprocessing. Specifically, we show an upper bound of n + 8 3(m+1) (n −m) character comparisons. This bound is achieved by an online algorithm which perfo...
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The paper considers the exact number of character comparisons needed to nd all occurrences of a pattern of length m in a text of length n using on-line and general algorithms. For on-line algorithms, a lower bound of about (1 + 9 4(m+1)) n character comparisons is obtained. For general algorithms, a lower bound of about (1 + 2 m+3) n character comparisons is obtained. These lower bounds complem...
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We show that the average number of characters examined to search for r random patterns of length m in a text of length n over a uniformly distributed alphabet of size σ cannot be less than Ω(n log σ (rm)/m). When we permit up to k insertions, deletions, and/or substitutions of characters in the occurrences of the patterns, the lower bound becomes Ω(n(k+ log σ (rm))/m). This generalizes previous...
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ژورنال
عنوان ژورنال: SIAM Journal on Computing
سال: 1997
ISSN: 0097-5397,1095-7111
DOI: 10.1137/s009753979324694x