PHP quick sort small example PHP quick sort implementation method

PHP quick sort small example PHP quick sort implementation method

Full code:

set_time_limit(0);
function quickSort($arr) {
 if (count($arr) > 1) { // Only judge the case when the array length is greater than 1
 $k = $arr[0]; // The default reference object is the first object in the array
 $x = array(); // Smaller than the reference
 $y = array(); // Larger than the reference
 $_size = count($arr);
 for ($i = 1; $i < $_size; $i++) {
 if ($arr[$i] <= $k) {
 $x[] = $arr[ $i];
 } else {
 $y[] = $arr[$i];
 }
 }
 // Arrange the arrays on both sides recursively
 $x = quickSort($x);
 $y = quickSort($y);
 return array_merge($x, array($k), $y);
 } else {
 return $arr;
 }
}
$test_array = array();
$n = 0;
//Test a record of 300,000
while(++$n<=300000){
 $test_array[$n] = $n;
}
echo 'Array init!';
 shuffle($test_array); //Shuffle the order
echo 'Array shuffled';
echo date( 'Y-m-d H:m:s').'';
$res = quickSort($test_array);
echo date('Y-m-d H:m:s');
?>

Quick sort idea: 1) Divide the target array into two arrays, with the first element as the basis by default; 2) If it is smaller than the reference object, it is allocated to the Left array, otherwise it is allocated to the Right array; 3) Follow this method until there is only one element in the array.