- /**
- * 递归法实现的快速排序
- * @param $seq
- * @return array
- */
- function quicksort($seq)
- {
- if (count($seq) > 1) {
- $k = $seq[0];
- $x = array();
- $y = array();
- $_size = count($seq); //do not use count($seq) in loop for.
- for ($i = 1; $i < $_size; $i++) {
- if ($seq[$i] <= $k) {
- $x[] = $seq[$i];
- } else {
- $y[] = $seq[$i];
- }
- }
- $x = quicksort($x);
- $y = quicksort($y);
- return array_merge($x, array($k), $y);
- } else {
- return $seq;
- }
- }
- /**用迭代实现
- * @param $seq
- * @return array
- */
- function quicksortX(&$seq)
- {
- $stack = array($seq);
- $sort = array();
- while ($stack) {
- $arr = array_pop($stack);
- if(count($arr) <= 1){
- if (count($arr) == 1) {
- $sort[] = &$arr[0];
- }
- continue;
- }
- $k = $arr[0];
- $x = array();
- $y = array();
- $_size = count($arr);
- for ($i = 1; $i < $_size; $i++) {
- if ($arr[$i] <= $k) {
- $x[] = &$arr[$i];
- } else {
- $y[] = &$arr[$i];
- }
- }
- !empty($y) && array_push($stack, $y);
- array_push($stack, array($arr[0]));
- !empty($x) && array_push($stack, $x);
- }
- return $sort;
- }
- //$testArr = array(5545, 5, 6, 7675, 100, 9, 233, 566, 789, 456, 23, 55, 7, 4, 343, 564, 5, 45657, 8, 998, 9, 34, 34, 55, 6, 5, 6433, 67, 6, 6766, 4, 2, 42, 25634, 34343, 3, 3, 454, 4, 65, 6678, 57, 5455);
- for($i=0;$i<20;$i++){
- $testArr[]=mt_rand(0,10000);
- }
- //var_dump($testArr);
- echo count($testArr).'<br>';
- $start=microtime();
- echo count(quicksort($testArr)).'<br>';
- echo microtime()-$start.'<br>';
- var_dump(quicksort($testArr));
- echo '------------------------------------------------------------------------<br>';
- echo count($testArr).'<br>';
- $start=microtime();
- echo count(quicksortX($testArr)).'<br>';
- echo microtime()-$start.'<br>';
- var_dump(quicksortX($testArr));
- //该片段来自于http://www.codesnippet.cn/detail/111120137022.html
来源: http://www.codesnippet.cn/detail/111120137022.html