Ehm ... what am I missing here? like IMHO just searching for a repeated digit like with /(\d).*\1/ and inverting the result should do.

  DB<111> print $_ !~ /(\d).*\1/ ? "$_ ok\n" :"$_ has <$1>\n" for qw/0
+12 0102 01233/
012 ok
0102 has <0>
01233 has <3>
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