regex - Negative lookahead with capturing groups -

i'm attempting challenge:

i want match strings don't contain abba pattern.

match:

aesthophysiology amphimictical baruria calomorphic

don't match

anallagmatic bassarisk chorioallantois coccomyces abba

firstly, have regex determine abba pattern.

(\w)(\w)\2\1

next want match strings don't contain pattern:

^((?!(\w)(\w)\2\1).)*$

however matches everything.

if simplify specifying literal negative lookahead:

^((?!agm).)*$

the regex not match string "anallagmatic", desired behaviour.

so looks issue me using capturing groups , back-references within negative lookahead.

^(?!.*(.)(.)\2\1).+$      ^^

you can use lookahead here.see demo.the lookahead created correct need add .* cannot appear anywhere in string.

your approach work if make first group non capturing.

^(?:(?!(\w)(\w)\2\1).)*$   ^^

see demo.it not working because \2 \1 different intended.in regex should have been \3 , \2.

TSQL