"abcdabcdabceabcdabcdabceab" =~ /(.+).*\1/

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returns 
abcdabcdabce

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Can you give more input samples to exemplify the other constraints?

لսႽ† ᥲᥒ⚪⟊Ⴙᘓᖇ Ꮅᘓᖇ⎱ Ⴙᥲ𝇋ƙᘓᖇ

In reply to Re: Finding repeat sequences. by choroba
in thread Finding repeat sequences. by BrowserUk

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