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Its length is n. P denotes the string to be searched for, called the pattern. Its length is m. S[i] denotes the character at index i of string S, counting from 1. S[i..j] denotes the substring of string S starting at index i and ending at j, inclusive. A prefix of S is a substring S[1..i] for some i in range [1, l], where l is the length of S.
If n is greater than the length of the string then most implementations return the whole string (exceptions exist – see code examples). Note that for variable-length encodings such as UTF-8 , UTF-16 or Shift-JIS , it can be necessary to remove string positions at the end, in order to avoid invalid strings.
The de Bruijn sequence for alphabet size k = 2 and substring length n = 2. In general there are many sequences for a particular n and k but in this example it is unique, up to cycling. In combinatorial mathematics , a de Bruijn sequence of order n on a size- k alphabet A is a cyclic sequence in which every possible length- n string on A occurs ...
A hash function or checksum can be used to reduce the size of the strings in the sequences. That is, for source code where the average line is 60 or more characters long, the hash or checksum for that line might be only 8 to 40 characters long.
Most strings in modern programming languages are variable-length strings. Of course, even variable-length strings are limited in length – by the size of available computer memory. The string length can be stored as a separate integer (which may put another artificial limit on the length) or implicitly through a termination character, usually ...
The closely related problem of finding a minimum-length string which is a superstring of a finite set of strings S = { s 1,s 2,...,s n} is also NP-hard. [2] Several constant factor approximations have been proposed throughout the years, and the current best known algorithm has an approximation factor of 2.475. [3]
The second case reduces to the first by splitting the string at the split point to create two new leaf nodes, then creating a new node that is the parent of the two component strings. For example, to split the 22-character rope pictured in Figure 2.3 into two equal component ropes of length 11, query the 12th character to locate the node K at ...
This subsequence has length six; the input sequence has no seven-member increasing subsequences. The longest increasing subsequence in this example is not the only solution: for instance, 0, 4, 6, 9, 11, 15 0, 2, 6, 9, 13, 15 0, 4, 6, 9, 13, 15. are other increasing subsequences of equal length in the same input sequence.