SHELL SORT

< ? php
function shell_sort(&$a)
{
$count = count($a);
$columns = 1;
while ($columns < $count)
{
$columns = $columns * 2 + 1;
}
$columns = ($columns – 1) / 2;
while ($columns > 0)
{
for ($c = 0; $c < $columns; $c++)
{
for ($i = $columns; $i < $count; $i += $columns)
{
$value = $a[$i];
for ($x = $i – $columns;( ($x >= 0) && ($a[$x] > $value) );$x -= $columns)
{
$a[$x + $columns] = $a[$x];
}
$a[$x + $columns] = $value;
}
}
$columns = ($columns – 1) / 2;
}
}
$values = array(7, 3, 4, 6, 1);
shell_sort($values);
foreach ($values as $v) { echo “{$v} “; }
?>