c# – 用于查找文本中所有关键字的高效算法

The 07001
algorithm is a string searching
algorithm invented by Alfred V. Aho
and Margaret J. Corasick. It is a kind
of dictionary-matching algorithm that
locates elements of a finite set of
strings (the “dictionary”) within an
input text. It matches all patterns
“at once”,so the complexity of the
algorithm is linear in the length of
the patterns plus the length of the
searched text plus the number of
output matches. Note that because all
matches are found,there can be a
quadratic number of matches if every
substring matches (e.g. dictionary =
a,aa,aaa,aaaa and input string is
aaaa).

The 07002 is a string searching algorithm created by Michael O. Rabin and Richard M. Karp in 1987 that uses hashing to find any one of a set of pattern strings in a text. For text of length n and p patterns of combined length m,its average and best case running time is O(n+m) in space O(p),but its worst-case time is O(nm). In contrast,the Aho–Corasick string matching algorithm has asymptotic worst-time complexity O(n+m) in space O(m).