1 /**
2 * 链表元素结点类
3 */
4 class Node {
5 public $pre = NULL; // 前驱
6 public $next = NULL; // 后继
7 public $data = NULL; // 结点值
8 public function __Construct($data) {
9 $this->data = $data;
10 }
11 }
12
13 /**
14 * 双向链表类
15 */
16 class DoubleLink {
17 private $head; // 头指针
18 private $tail; // 尾指针
19 private $len; // 链表长度
20
21 /**
22 * 初始化链表
23 */
24 public function __Construct()
25 {
26 $newNode = $newNode = new Node(null);
27 $this->tail = $this->head = $newNode;
28 $this->len = 0;
29 }
30
31 /**
32 * 添加结点
33 * @param $data 要添加的结点
34 * @param $search 添加的位置
35 */
36 public function addNode($data, $search = null) {
37 $newNode = new Node($data);
38 $tmp = $this->searchNode($search);
39 if ($tmp !== null) {
40 $newNode->pre = $tmp->pre;
41 $newNode->next = $tmp;
42 $tmp->pre = $newNode;
43 $newNode->pre->next = $newNode;
44 } else {
45 $newNode->pre = $this->tail;
46 $this->tail->next = $newNode;
47 $this->tail = $newNode;
48 }
49 $this->len++;
50 }
51
52 /**
53 * 删除指定结点
54 * @param $search
55 */
56 public function delNode($search) {
57 $tmp = $this->searchNode($search);
58 if(null !== $tmp){
59 if ($tmp->next !== null) {
60 $tmp->pre->next = $tmp->next;
61 $tmp->next->pre = $tmp->pre;
62 } else {
63 $tmp->pre->next = null;
64 }
65 unset($tmp);
66 $this->len--;
67 }
68 }
69
70 /**
71 * 修改指定结点的值
72 * @param $search
73 * @param $data
74 */
75 public function setNode($search, $data){
76 $tmp = $this->searchNode($search);
77 if(null !== $tmp){
78 $tmp->data = $data;
79 }
80 }
81
82 /**
83 * 查找结点
84 * @param $search 要查找的结点元素值
85 * @return $tmp 查找到的结点元素
86 */
87 public function searchNode($search) {
88 $tmp = $this->head;
89 while ( $tmp->next !== null ) {
90 $tmp = $tmp->next;
91 if ($tmp->data === $search) {
92 return $tmp;
93 }
94 }
95 return null;
96 }
97
98 /**
99 * 读取链表全部结点
100 */
101 public function show() {
102 $tmp = $this->head;
103 while ( $tmp->next !== null ) {
104 $tmp = $tmp->next;
105 echo $tmp->data;
106 }
107 echo "<br/>";
108 $tmp = $this->tail;
109 while ( $tmp->pre !== null ) {
110 echo $tmp->data;
111 $tmp = $tmp->pre;
112 }
113 }
114 }
115
116 $myList = new DoubleLink();
117 $myList->addNode("A");
118 $myList->addNode("B");
119 $myList->addNode("C");
120 $myList->addNode("D");
121 $myList->addNode("E");
122 $myList->addNode('F','C');
123 $myList->delNode('F');
124 $myList->setNode("B",'G');
125 $myList->show();
