php版快速排序

来源：互联网发布：centos架设web服务器编辑：程序博客网时间：2024/05/18 02:12

今天写了一下php版的插入排序和快速排序，比较一下两者的速度

<?phpclass SortAlgorithm {protected $_data;public function setData($data) {$this->_data = $data;}public function getData() {return $this->_data;}public function isort3() {$x = $this->_data;for ($i=1; $i < count($x); $i++) { $t = $x[$i];for ($j=$i; $j > 0 && $x[$j-1] > $t; $j--) { $x[$j] = $x[$j-1];}$x[$j] = $t;}return $x;}/** * @param  [type] $l [description] * @param  [type] $u [description] * @param  [type] $x [description] * @return [type]    [description] */public function qsort_slow($l, $u, $x) {if ($l >= $u) return $x;$m = $l;for ($i=$l+1; $i <= $u; $i++) { if ($x[$i] < $x[$l])list($x[$m], $x[$i]) = array($x[$i], $x[++$m]);}list($x[$l], $x[$m]) = array($x[$m], $x[$l]);$x = $this->qsort_slow($l, $m-1, $x);$x = $this->qsort_slow($m+1, $u, $x);return $x;}}$x = Array();$n = $_SERVER['argv'][1];for($i = 0; $i < $n; $i ++) {$x[] = rand();}$algorithmIns = new SortAlgorithm();$start = time();$algorithmIns->setData($x);$sorted_x = $algorithmIns->isort3();$used = time() - $start;$start = time();echo "isort:{$used}\n";$sorted_x1 = $algorithmIns->qsort_slow(0, $n -1, $x);$used = time() - $start;$start = time();echo "qsort:{$used}\n";

排序1万条数据需要时间分别为：

isort:6
qsort:7

试了几次，快排时间都比插入排序要长

重写了一下，在参数里不传数组：

<?phpclass SortAlgorithm {protected $_data;public function setData($data) {$this->_data = $data;}public function getData() {return $this->_data;}public function isort3() {$x = $this->_data;for ($i=1; $i < count($x); $i++) { $t = $x[$i];for ($j=$i; $j > 0 && $x[$j-1] > $t; $j--) { $x[$j] = $x[$j-1];}$x[$j] = $t;}return $x;}/** * 慢版，由于需要递归地赋值x变量，所以很慢 * @param  [type] $l [description] * @param  [type] $u [description] * @param  [type] $x [description] * @return [type]    [description] */public function qsort_slow($l, $u, $x) {if ($l >= $u) return $x;$m = $l;for ($i=$l+1; $i <= $u; $i++) { if ($x[$i] < $x[$l])list($x[$m], $x[$i]) = array($x[$i], $x[++$m]);}list($x[$l], $x[$m]) = array($x[$m], $x[$l]);$x = $this->qsort_slow($l, $m-1, $x);$x = $this->qsort_slow($m+1, $u, $x);return $x;}public function qsort1($l, $u) {if ($l >= $u) return true;$m = $l;for ($i=$l+1; $i <= $u; $i++) { if ($this->_data[$i] < $this->_data[$l])list($this->_data[$m], $this->_data[$i]) = array($this->_data[$i], $this->_data[++$m]);}list($this->_data[$l], $this->_data[$m]) = array($this->_data[$m], $this->_data[$l]);$this->qsort1($l, $m-1);$this->qsort1($m+1, $u);return true;}}$x = Array();$n = $_SERVER['argv'][1];for($i = 0; $i < $n; $i ++) {$x[] = rand();}$algorithmIns = new SortAlgorithm();$start = time();$algorithmIns->setData($x);$sorted_x = $algorithmIns->isort3();$used = time() - $start;$start = time();echo "isort:{$used}\n";$algorithmIns->setData($x);$sorted_x1 = $algorithmIns->qsort1(0, $n -1, $x);$used = time() - $start;$start = time();echo "qsort:{$used}\n";

执行一下，速度立马飙升：

isort:6
qsort:0

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