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run code in 300+ PHP versions simultaneously
<?php error_reporting(0); $a = "abcdefffefa"; for($i = 0; $i < 10; $i++) $a = $a . $a; $b = "afe"; print(str_replace(array_unique(str_split($b)), "", $a));

preferences:
52.2 ms | 402 KiB | 5 Q