Oh boy what a beautiful regex. I'm sure it does something logical and easy to understand.
^.?$|^(..+?)\1+$ ::: spoiler <answer> Matches strings of any character repeated a non-prime number of times ::: https://www.youtube.com/watch?v=5vbk0TwkokM [https://www.youtube.com/watch?v=5vbk0TwkokM]
No cookie for me I just tried it in Notepad++ and VS code and it matches lines of one characer (first group I think) or the starting of a line that is an at least 2 characters string repeated twice (second group it seems)
so the second group matches
abab
abcabc
abcdeabce
abcdefabcdef
Nothing about prime numbers really only first repetition gets a match. Very interesting Honestly I used regex from years and never had to retort to something like this ever. I can only imagine it useful to check for a password complexity to not be repeated strings like I do for sites that I just want in and use a yopmail.com mail to register a fake user.
NateNate60
S_H_K