Shell sort

[make-github-pseudonymous-again]

https://en.wikipedia.org/wiki/Shellsort

[make-github-pseudonymous-again]

Example in PHP

function shellSort(&$a) {
    $n = count($a);
    $d = floor($n / 2);
    while ($d > 0) {
        for ($i = 0; $i < ($n - $d); $i++) {
            $j = $i;
            while ($j >= 0 && $a[$j] > $a[$j + $d]) {
                list($a[$j], $a[$j + $d]) = array($a[$j + $d], $a[$j]);
                $j--;
            }
        }
        $d = floor($d / 2);
    }
}