algo/php/12_sort/quicksort.php
2018-10-31 09:24:07 +08:00

47 lines
800 B
PHP

<?php
function quickSort(array &$a)
{
$n = count($a);
quickSortInternally($a, 0, $n-1);
}
function quickSortInternally(array &$a, int $l, int $r)
{
if ($l >= $r) return;
$q = partition($a, $l, $r);
quickSortInternally($a, $l, $q-1);
quickSortInternally($a, $q+1, $r);
}
function partition(&$a, $l, $r): int
{
$pivot = $a[$r];
$i = $l;
for ($j = $l; $j < $r; ++$j) {
if ($a[$j] < $pivot) {
[$a[$j], $a[$i]] = [$a[$i], $a[$j]];
++$i;
}
}
[$a[$r], $a[$i]] = [$a[$i], $a[$r]];
return $i;
}
$a1 = [1,4,6,2,3,5,4];
$a2 = [2, 2, 2, 2];
$a3 = [4, 3, 2, 1];
$a4 = [5, -1, 9, 3, 7, 8, 3, -2, 9];
quickSort($a1);
print_r($a1);
quickSort($a2);
print_r($a2);
quickSort($a3);
print_r($a3);
quickSort($a4);
print_r($a4);