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<?php function accum($s) { $split = str_split($s, 1); $out = ''; foreach ($split as $idx => $char) { if ($idx > 0) { $out .= '-'; } $out .= ucfirst(str_repeat($char, $idx + 1)); } return $out; } echo accum('zpglnrxqenu');

preferences:
59.94 ms | 402 KiB | 5 Q