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Examples of two quick sort algorithms in PHP_PHP tutorial

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Release： 2016-07-13 10:06:29

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Examples of two quick sorting algorithms in PHP

This article mainly introduces examples of two quick sorting algorithms in PHP. This article directly gives the implementation code, using the recursive method and the iterative method respectively. Implementation, friends who need it can refer to it

Although in web application development like PHP, we don’t emphasize the importance of sorting too much, because PHP itself already comes with powerful sorting functions such as sort(), but in some important occasions, such as some high-level In the case of concurrency, I think the impact of the sorting algorithm cannot be ignored. So here we introduce recursive sorting and iterative sorting.

Recursive method:

/**

* 递归法实现的快速排序

function quicksort($seq)

{

$k = $seq[0];

$x = array();

$y = array();

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;

}

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/**

* 迭代法的快速排序

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;

}

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/** * Quick sort implemented by recursive method */ function quicksort($seq) { $k = $seq[0]; $x = array(); $y = array(); for($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; } }

Iterative method: ?

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/** * Quick sort using iterative method */ 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; }

使用：

/**

*产生一个随机数组

for($i=0;$i<5;$i++){

$testArr[]=mt_rand(0,100);

}

var_dump($testArr);

var_dump(quicksort($testArr));

var_dump(quicksortx($testArr));

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/** *Generate a random array

*/ for($i=0;$i<5;$i++){ $testArr[]=mt_rand(0,100); } var_dump($testArr); var_dump(quicksort($testArr)); var_dump(quicksortx($testArr));

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