$_ = "helloworldhellohellohihellohiworld";
m{
  (?{ local ($c1, $c2, $c3) = (0,0,0) })
  ^
  (.+?)
  (?:
    \1 (?{ local $c1 = $c1 + 1 })
  )*
  (.+?)
  (?:
    (?: \1 (?{ local $c1 = $c1 + 1 }) )
    |
    (?: \2 (?{ local $c2 = $c2 + 1 }) )
  )*
  (.+?)
  (?:
    (?: \1 (?{ local $c1 = $c1 + 1 }) )
    |
    (?: \2 (?{ local $c2 = $c2 + 1 }) )
    |
    (?: \3 (?{ local $c3 = $c3 + 1 }) )
  )*
  (?(?{ $c1 && $c2 && $c3 })|(?!))
  $
}x and print "<$1> <$2> <$3>\n";
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_____________________________________________________
Jeff[japhy]Pinyan: Perl, regex, and perl hacker.
s++=END;++y(;-P)}y js++=;shajsj<++y(p-q)}?print:??;