PHPにおけるハノイ塔問題の再帰アルゴリズムと反復アルゴリズムの実装

この記事では、PHP でのハノイの塔問題の再帰アルゴリズムと反復アルゴリズムの実装を紹介します。必要な友人はそれを参照できるようにします

。

プログラムコードアドレス: https://github.com/ParrySMS/Exp/tree/master/ProLang/hannota

再帰メソッド hannoRec.php

<?php/**
 * Created by PhpStorm.
 * User: L
 * Date: 2018-4-15
 * Time: 2:07
 *//** 递归实现
 * @param $id //盘子编号
 * @param $first //起点柱子
 * @param $middle //中介柱子
 * @param $end //终点柱子
 */function hanRec($id, $first, $middle, $end,$counter){
    if ($id == 1) {
        move(1,$first,$end,$counter);
    } else {
        hanRec($id-1,$first,$end,$middle,$counter);
        move($id,$first,$end,$counter);        $counter++;
        hanRec($id-1,$middle,$first,$end,$counter);
    }
}function move($id,$from,$to,$counter){
    global $counter;    $counter++;   // echo "step: $counter, level $id from $from move to $to, <br/>";}

hannoRec.php

<?php/**
 * Created by PhpStorm.
 * User: L
 * Date: 2018-4-17
 * Time: 2:38
 */class Params{ //定义一个对象来保存参数状态
    public $id;    public $num;    public $first;    public $middle;    public $end;    public $counter;    /**
     * Params constructor.
     * @param $num
     * @param $first
     * @param $middle
     * @param $end
     * @param $counter
     */
    public function __construct($id,$num, $first, $middle, $end, $counter)
    {
        $this->id = $id;        $this->num = $num;        $this->first = $first;        $this->middle = $middle;        $this->end = $end;        $this->counter = $counter;
    }

}function hanIter($id,$num, $first, $middle, $end, $counter){
    $stack =init($id,$num, $first, $middle, $end, $counter);    while($stack){        //出栈
        $action = array_pop($stack);       // var_dump($action);
        if($action->num ==1){
            move($action->id,$action->first,$action->end,$action->counter);
        }else{            //入栈
            $next_stack = init($action->id,$action->num,$action->first, $action->middle, $action->end, $action->counter);            $stack=array_merge($stack,$next_stack);
        }
    }

}/** 入栈操作
 * @param $id //需要移动的盘子
 * @param $num //移动该盘子需要挪动的总盘子数量
 * @param $first
 * @param $middle
 * @param $end
 * @param $counter
 * @return array
 */function init($id,$num,$first, $middle, $end, $counter){
    unset($stack);    //注意入站出站顺序
    $stack = array();    //第一次回调
    $stack[] =new Params($id-1,$num-1,$middle,$first,$end,$counter);    //第二次回调
    $stack[] =new Params($id,1,$first, $middle, $end, $counter);    //第三次回调
    $stack[] =new Params($id-1,$num-1,$first,$end,$middle,$counter);    return $stack;

}/** 若在测试用例中，由于两个文件都有此 move函数，函数重名，注释掉其中一个即可 

function move($id,$from,$to,$counter){
    global $counter;
    $counter++;
   // echo "step: $counter, level $id from $from move to $to, <br/>";
}

**/

---

迭代法 hannoIter反復メソッド hannoIter

<?php/**
 * Created by PhpStorm.
 * User: L
 * Date: 2018-4-17
 * Time: 2:18
 */require "hannoRec.php";require "hannoIter.php";



define(&#39;TIMES&#39;, 100);
define(&#39;NUM&#39;, 10);function rowTable(){
    unset($row);    $row = array();    for ($i = 0; $i < TIMES; $i++) {    $row = getSortRow($row);
    }    foreach ($row as $r) {        print <<< TR
 <tr>
       <td>$r->iter</td>
       <td>$r->rec</td>
    </tr>
TR;
    }
}function getSortRow(array $row){
    $num = NUM;    $counter= 0;    $stime = microtime(true);
    hanIter($num, $num, &#39;A&#39;, &#39;B&#39;, &#39;C&#39;, $counter);    $etime = microtime(true);    $iterTime = 1000 * ($etime - $stime);//    echo "<br/>";
    $counter = 0;    $num = NUM;    $stime = microtime(true);
    hanRec($num, &#39;A&#39;, &#39;B&#39;, &#39;C&#39;, $counter);    $etime = microtime(true);    $recTime = 1000 * ($etime - $stime);    $row[] = (object)["iter" => $iterTime, "rec" => $recTime];    return $row;
}?><table border="1">
    <tr>
        <th>迭代 Iter/ms</th>
        <th>递归 Rec/ms</th>
    </tr>    <?php rowTable(); ?></table>

---

実行時間テストスクリプトtest.php

rrreee

参考

反復方法のアイデア:https://wenku.baidu.com/view/dce79165b0717fd5360cdcdb.html

関連する推奨事項:

php 再帰関数 分析例

PHP 再帰アルゴリズムの簡略化

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