PhP中的排列组合 [英] Permutation and Combination in PhP
本文介绍了PhP中的排列组合的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！
问题描述
我想从数组[1,2,3,4,5]计算排列5p2、5p3、5p4和5p5下面的功能仅运行5p5.要运行5p2、5p3、5p4，我将不得不使用for ... loop手动遍历数组.请帮助我.
I I want to compute the permutations 5p2, 5p3, 5p4 and 5p5 from the array [1,2,3,4,5] The function below only runs 5p5. To run 5p2, 5p3, 5p4 I will have to manually iterate through the array using a for...loop. Please help me.
//function to return permutations 5p5 array
function combinationArray($myarr) {
$results = [];
$current = [];
$next = function($myarr) use(&$next,&$results,&$current) {
$l = count($myarr);
if($l === 1) {
$current []= $myarr[0];
$results []= intval(implode($current)); //use this for array containing numbers only
//$results []= implode($current); //use this for array containing alphabets
array_pop($current);
return;
}
for($i=0; $i<$l; $i++) {
$tmpArr = $myarr;
$current []= array_splice($tmpArr,$i,1)[0];
$next($tmpArr);
array_pop($current);
}
};
$next($myarr);
return $results;
}
//5c2的手动迭代将是这样....大约有120个不同的模块.....
//Manual iteration of 5c2 will be like this....about 120 different modules.....
$wordArray = str_split($sWord, 1);
$newArray1 = $wordArray[0]; $newArray2 = $wordArray[1];$newArray3 = $wordArray[2]; $newArray4 = $wordArray[3]; $newArray5 = $wordArray[4];
//12
for($a = 0; $a < count($newArray1); $a++){
for($b = 0; $b < count($newArray2); $b++){
$aux = $newArray1[$a].$newArray2[$b]; array_push($result52, $aux);
}
}
//13
for($a = 0; $a < count($newArray1); $a++){
for($c = 0; $c < count($newArray3); $c++){
$aux = $newArray1[$a].$newArray3[$c]; array_push($result52, $aux);
}
}
//14
for($a = 0; $a < count($newArray1); $a++){
for($d = 0; $d < count($newArray4); $d++){
$aux = $newArray1[$a].$newArray4[$d]; array_push($result52, $aux);
}
}
//15
for($a = 0; $a < count($newArray1); $a++){
for($e = 0; $e < count($newArray5); $e++){
$aux = $newArray1[$a].$newArray5[$e]; array_push($result52, $aux);
}
}
//21
for($b = 0; $b < count($newArray2); $b++){
for($a = 0; $a < count($newArray1); $a++){
$aux = $newArray2[$b].$newArray1[$a]; array_push($result52, $aux);
}
}
//23
for($b = 0; $b < count($newArray2); $b++){
for($c = 0; $c < count($newArray3); $c++){
$aux = $newArray2[$b].$newArray3[$c]; array_push($result52, $aux);
}
}
//24
for($b = 0; $b < count($newArray2); $b++){
for($d = 0; $d < count($newArray4); $d++){
$aux = $newArray2[$b].$newArray4[$d]; array_push($result52, $aux);
}
}
//25
for($b = 0; $b < count($newArray2); $b++){
for($e = 0; $e < count($newArray5); $e++){
$aux = $newArray2[$b].$newArray5[$e]; array_push($result52, $aux);
}
}
//31
for($c = 0; $c < count($newArray3); $c++){
for($a = 0; $a < count($newArray1); $a++){
$aux = $newArray3[$c].$newArray1[$a]; array_push($result52, $aux);
}
}
//32
for($c = 0; $c < count($newArray3); $c++){
for($b = 0; $b < count($newArray2); $b++){
$aux = $newArray3[$c].$newArray2[$b]; array_push($result52, $aux);
}
}
//34
for($c = 0; $c < count($newArray3); $c++){
for($d = 0; $d < count($newArray4); $d++){
$aux = $newArray3[$c].$newArray4[$d]; array_push($result52, $aux);
}
}
//35
for($c = 0; $c < count($newArray3); $c++){
for($e = 0; $e < count($newArray5); $e++){
$aux = $newArray3[$c].$newArray5[$e]; array_push($result52, $aux);
}
}
//41
for($d = 0; $d < count($newArray4); $d++){
for($a = 0; $a < count($newArray1); $a++){
$aux = $newArray4[$d].$newArray1[$a]; array_push($result52, $aux);
}
}
//42
for($d = 0; $d < count($newArray4); $d++){
for($b = 0; $b < count($newArray2); $b++){
$aux = $newArray4[$d].$newArray2[$b]; array_push($result52, $aux);
}
}
//43
for($d = 0; $d < count($newArray4); $d++){
for($c = 0; $c < count($newArray3); $c++){
$aux = $newArray4[$d].$newArray3[$c]; array_push($result52, $aux);
}
}
//45
for($d = 0; $d < count($newArray4); $d++){
for($e = 0; $e < count($newArray5); $e++){
$aux = $newArray4[$d].$newArray5[$e]; array_push($result52, $aux);
}
}
//51
for($e = 0; $e < count($newArray5); $e++){
for($a = 0; $a < count($newArray1); $a++){
$aux = $newArray5[$e].$newArray1[$a]; array_push($result52, $aux);
}
}
//52
for($e = 0; $e < count($newArray5); $e++){
for($b = 0; $b < count($newArray2); $b++){
$aux = $newArray5[$e].$newArray2[$b]; array_push($result52, $aux);
}
}
//53
for($e = 0; $e < count($newArray5); $e++){
for($c = 0; $c < count($newArray3); $c++){
$aux = $newArray5[$e].$newArray3[$c]; array_push($result52, $aux);
}
}
//54
for($e = 0; $e < count($newArray5); $e++){
for($d = 0; $d < count($newArray4); $d++){
$aux = $newArray5[$e].$newArray4[$d]; array_push($result52, $aux);
}
}
$result52 = array_unique($result52); //remove duplicates... but the indexes dont align.
$result52 = array_reduce($result52,"myfunction");//convert the array into a string bcos of the indexes
$result52 = str_split($result52, 2); //split the new string in twos into an array to get correct indexes
print_r($result52);
谢谢大家.
推荐答案
我在互联网上钓鱼了一些东西.我希望这能满足您的需求.
I fished some things in the internet. I hope this suits your needs.
对此我不负任何责任.这是两种解决方案的组合:生成电源集和实现堆算法
I don't take any credit for this. It's a combination of these two solutions: Generating a Power Set and Implementing Heap's Algorithm
<?php
$arr1 = [1,2,3];
/**
* Permutation.
*/
class Permutation
{
/**
* @var array
*/
protected $items;
/**
* @var array
*/
protected $result = [];
/**
* @param array $array
* @param int $permutation
*/
public function __construct($array, $permutation)
{
if (count($array) < $permutation) {
throw new Exception("That's impossible for me :/");
}
// first get all the unique subsets with the permutation's length
$subsets = $this->getPowerSet($array, $permutation);
// genereate the permutation for each subset
foreach ($subsets as $subset) {
$this->setItems($subset)->heaps($this->n, $this->items);
}
sort($this->result);
}
/**
* Get result.
*
* @return array
*/
public function getResult()
{
return $this->result;
}
/**
* Set items.
*
* @param array $items
*/
public function setItems($items)
{
$this->items = $items;
$this->n = count($items);
return $this;
}
private function swap(&$items, $i, $j)
{
$temp = $items[$i];
$items[$i] = $items[$j];
$items[$j] = $temp;
}
/**
* This is Heap's algorithm, generates all possible permutations of n items.
*
* @link https://en.wikipedia.org/wiki/Heap%27s_algorithm
*
* @param int $n
* @param array $items
*/
private function heaps($n, &$items)
{
if ($n == 1) {
$this->result[] = implode('', $items);
} else {
for ($i = 0; $i < $n; ++$i) {
$this->heaps($n - 1, $items);
if ($n % 2 == 0) {
$this->swap($items, 0, $n - 1);
} else {
$this->swap($items, $i, $n - 1);
}
}
}
}
/**
* Way to get the Power Set (set of all unique subsets)
*
* @link https://www.php.net/manual/en/function.shuffle.php#88408
*
* @param array $in
* @param int $length
*/
private function getPowerSet($in, $length) {
$count = count($in);
$members = pow(2,$count);
$return = array();
for ($i = 0; $i < $members; $i++) {
$b = sprintf("%0".$count."b",$i);
$out = array();
for ($j = 0; $j < $count; $j++) {
if ($b{$j} == '1') $out[] = $in[$j];
}
if (count($out) === $length) {
$return[] = $out;
}
}
return $return;
}
}
$permutation = new Permutation($arr1, 2);
echo "<pre>";
print_r($permutation->getResult());
echo "</pre>";
这篇关于PhP中的排列组合的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！
查看全文
