PHP Unidirectional list reversal reverse (no empty head node)

* Refer to PHP standard library design interface

http://php.net/manual/en/class.spldoublylinkedlist.php

* Reverse one-way linked list

Reverse methods, other methods for the convenience of testing

<?php/** * Created by Phpstorm.    * USER:MCH * DATE:8/11/18 * time:00:25 */class Node {public $value;    Public $next;        Public function __construct ($data) {$this->value = $data;    $this->next = null;    }} class LinkedList implements Iterator, countable {private $head;     Private $cur;    Public Function __construct () {$this->head = $this->cur = null;    } public Function IsEmpty () {return is_null ($this->head);        Public function count () {$p = $this->head;        $count = 0;            while ($p!== null) {$p = $p->next;        $count + +;    } return $count;        Public function current () {if ($this->isempty ()) {return null;    } return $this->cur->value;        Public function Next () {if (Is_null ($this->cur)) {return null;    } $this->cur = $this->cur->next;    } Public Function Rewind () {    $this->cur = $this->head;    } public Function valid () {return!is_null ($this->cur);        Public Function key () {$p = $this->head;        $key = 0;            while ($p!== $this->cur) {$p = $p->next;        $key + +;    } return $key;            The public function push ($value) {if ($this->isempty ()) {$this->head = new Node ($value);        $this->cur = $this->head;            } else {$this->cur = $this->head;            while ($this->cur->next!== null) {$this->cur = $this->cur->next;        } $this->cur->next = new Node ($value);    } return $this;        The Public function ForEach (callable $callback, mixed $userdata = null) {$this->rewind ();            while ($this->valid ()) {Call_user_func ($callback, $this->current (), $this->key (), $userdata);        $this->next ();   }    }  Public Function reverse () {if ($this->isempty ()) return;        if ($this->count () < 2) return;        $prev = null;        $cur = $this->head;            while ($cur) {//save next $next = $cur->next;            Move cur to head $this->head = $cur;            $cur->next = $prev;            Iterate $prev = $cur;        $cur = $next; }    } }

　　

* Test

$list = new LinkedList (); for ($i = N, $i <, $i + +) {    $list->push (Chr ($i)),} $list->foreach (function ($value, $index) {    printf (" [%d] =%s<br/> ", $index, $value);}); Echo '-------------------<br/> '; $list->reverse (); $list->foreach (function ($value, $index) {    printf ("[%d] =%s<br/>", $index, $value);});

　　

* Output:

[0] = A
[1] = B
[2] = C
[3] = D
[4] = = E
[5] = F

....

-------------------
[0] = Z
[1] = Y
[2] = X
[3] = W
[4] = V
[5] = = U
...

PHP Unidirectional list reversal reverse (no empty head node)