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I need to get the following regex to pass at https://regex101.com I will include

ID: 3753424 • Letter: I

Question

I need to get the following regex to pass at https://regex101.com I will include the tests cases and what i have so far for the regex expression..

All words in which a is tripled and b is tripled, but not both. This means each word contains the substring aaa or the substring bbb but not both

This is the following regex expression that I currently have but still cant get it to pass all the test cases
^(((a|ba|bba)*|((bb|b|)))aaa(a|ba|bba)*|(bb|b|)|(((b|ab|aab)*|(aa|a|))bbb((b|ab|aab))*|(aa|a|)))$

These strings should have FULL matching

aaa

bbb

baaab

abbba

abbb

bbba

baaa

aaab

abaaaab

aaaaaaa

bbbbbbb

bbaaabb

These strings should NOT have FULL matching:

bbbaaa

aaabbb

abba

a

b

ab

ba

abab

aabb

aaababababbb

bbbabababaaa

Explanation / Answer

aaa(?!bbb)|(?<!bbb)aaa

I have tried but try to build more upon this

aaa(?!bbb) - matches a aaa only if is not followed by bbb, but bbb will not be part of the overall regex match

(?<!bbb)aaa - matches a aaa only if is not preceded by an bbb, but bbb will not be part of the overall regex match

I hope this helps.