Implementation of recursive algorithm and iterative algorithm for Tower of Hanoi problem in PHP

This article introduces the recursive algorithm implementation and iterative algorithm implementation of the Tower of Hanoi problem in PHP. It has a certain reference value. Now I share it with you. Friends in need can refer to it

implementation Code

Program code address: https://github.com/ParrySMS/Exp/tree/master/ProLang/hannota

Recursive method 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/>";}

---

Iteration methodhannoIter

<?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/>";
}

**/

---

Execution time test script test.php

<?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>

Reference

Iterative method ideas: https://wenku.baidu.com/view/dce79165b0717fd5360cdcdb.html

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