Pattern Matching with Variables: Fast Algorithms and New Hardness Results

نویسندگان

  • Henning Fernau
  • Florin Manea
  • Robert Mercas
  • Markus L. Schmid
چکیده

A pattern (i. e., a string of variables and terminals) maps to a word, if this is obtained by uniformly replacing the variables by terminal words; deciding this is NP-complete. We present efficient algorithms1 that solve this problem for restricted classes of patterns. Furthermore, we show that it is NP-complete to decide, for a given number k and a word w, whether w can be factorised into k distinct factors; this shows that the injective version (i. e., different variables are replaced by different words) of the above matching problem is NP-complete even for very restricted cases. 1998 ACM Subject Classification F.2.2 Nonnumerical Algorithms and Problems, F.4.3 Formal Languages

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تاریخ انتشار 2015