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Regex Roulette · #51 · 2026-05-25

Match strings with a repeated character (aa, bb, etc.)

Difficulty 2/3

How to play

Write a regex that matches all green strings and rejects all red strings. Live feedback shows which strings pass. Shorter patterns score better.

Must match

  • aardvark — not yet evaluated
  • book — not yet evaluated
  • hello — not yet evaluated
  • committee — not yet evaluated

Must not match

  • abc — not yet evaluated
  • cat — not yet evaluated
  • dog — not yet evaluated
  • unique — not yet evaluated

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Pattern body only — slashes and flags (e.g. /g, /i) aren't part of the input.

0/200 chars

Type a regex that matches all green strings and rejects all red strings · Back to hub