time complexity is O(n)

Good kata.

I propose creating an version for 1kyu, by adding "[...]", quantifiers {m,n}, non greedy "*+?", escaping, multiple "or", and lookaheads "(?=...)/(?!...)"

[ab^cd]: new Chars('ab', 'cd')
regex{m,n}: new Times(regex, m, n)
etc

Yes, this is not "code challenge".
Solving this problem is only an idea (in the form of a set of 3*m integers), and it does not matter how it will be framed. The length of the array also has no special meaning. 99 is enough to find the common idea for any odd length, not to use brute force.