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<?php $xmls = [6, 3, 2, 5, 4, 1]; echo memory_get_usage() . "\n\n"; usort($xmls, function($a, $b) { static $documents = array(); if (!isset($documents[$a])) { $documents[$a] = true; } if (!isset($documents[$b])) { $documents[$b] = true; } echo memory_get_usage() . "\n" . print_r($documents) . "\n"; if ($documents[$a] == $documents[$b]) { return 0; } return $documents[$a] < $documents[$b] ? -1 : 1; }); print_r($xmls);

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32.92 ms | 402 KiB | 5 Q