Merge pull request wangzheng0822#51 from Hkesd/master

php 08_stack

php/06_linkedlist/SingleLinkedList.php

@@ -133,7 +133,7 @@ public function getPreNode(SingleLinkedListNode $node)
         $preNode = $this->head;
         // 遍历找到前置节点 要用全等判断是否是同一个对象
         // http://php.net/manual/zh/language.oop5.object-comparison.php
-        while ($curNode !== $node) {
+        while ($curNode !== $node && $curNode != null) {
             $preNode = $curNode;
             $curNode = $curNode->next;
         }

php/08_stack/StackOnLinkedList.php

@@ -0,0 +1,159 @@
+<?php
+/**
+ * User: lide01
+ * Date: 2018/10/11 19:37
+ * Desc:
+ */
+
+namespace Algo_08;
+
+
+use Algo_06\SingleLinkedListNode;
+
+class StackOnLinkedList
+{
+    /**
+     * 头指针
+     *
+     * @var SingleLinkedListNode
+     */
+    public $head;
+
+    /**
+     * 栈长度
+     *
+     * @var
+     */
+    public $length;
+
+    /**
+     *
+     * StackOnLinkedList constructor.
+     */
+    public function __construct()
+    {
+        $this->head = new SingleLinkedListNode();
+        $this->length = 0;
+    }
+
+    /**
+     * 出栈
+     *
+     * @return bool
+     */
+    public function pop()
+    {
+        if (0 == $this->length) {
+            return false;
+        }
+
+        $this->head->next = $this->head->next->next;
+        $this->length--;
+
+        return true;
+    }
+
+    /**
+     * 入栈
+     *
+     * @param $data
+     *
+     * @return SingleLinkedListNode|bool
+     */
+    public function push($data)
+    {
+        return $this->pushData($data);
+    }
+
+    /**
+     * 入栈 node
+     *
+     * @param SingleLinkedListNode $node
+     *
+     * @return bool
+     */
+    public function pushNode(SingleLinkedListNode $node)
+    {
+        if (null == $node) {
+            return false;
+        }
+
+        $node->next = $this->head->next;
+        $this->head->next = $node;
+
+        $this->length++;
+        return true;
+    }
+
+    /**
+     * 入栈 data
+     *
+     * @param $data
+     *
+     * @return SingleLinkedListNode|bool
+     */
+    public function pushData($data)
+    {
+        $node = new SingleLinkedListNode($data);
+
+        if (!$this->pushNode($node)) {
+            return false;
+        }
+
+        return $node;
+    }
+
+    /**
+     * 获取栈顶元素
+     *
+     * @return SingleLinkedListNode|bool|null
+     */
+    public function top()
+    {
+        if (0 == $this->length) {
+            return false;
+        }
+
+        return $this->head->next;
+    }
+
+    /**
+     * 打印栈
+     */
+    public function printSelf()
+    {
+        if (0 == $this->length) {
+            echo 'empty stack' . PHP_EOL;
+            return;
+        }
+
+        echo 'head.next -> ';
+        $curNode = $this->head;
+        while ($curNode->next) {
+            echo $curNode->next->data . ' -> ';
+
+            $curNode = $curNode->next;
+        }
+        echo 'NULL' . PHP_EOL;
+    }
+
+    /**
+     * 获取栈长度
+     *
+     * @return int
+     */
+    public function getLength()
+    {
+        return $this->length;
+    }
+
+    /**
+     * 判断栈是否为空
+     *
+     * @return bool
+     */
+    public function isEmpty()
+    {
+        return $this->length > 0 ? false : true;
+    }
+}

php/08_stack/main.php

@@ -0,0 +1,32 @@
+<?php
+/**
+ * User: lide01
+ * Date: 2018/10/11 20:01
+ * Desc:
+ */
+
+namespace Algo_08;
+
+require_once '../vendor/autoload.php';
+
+$stack = new StackOnLinkedList();
+$stack->pushData(1);
+$stack->pushData(2);
+$stack->pushData(3);
+$stack->pushData(4);
+var_dump($stack->getLength());
+$stack->printSelf();
+
+$topNode = $stack->top();
+var_dump($topNode->data);
+
+$stack->pop();
+$stack->printSelf();
+$stack->pop();
+$stack->printSelf();
+
+var_dump($stack->getLength());
+
+$stack->pop();
+$stack->pop();
+$stack->printSelf();

php/README.md

@@ -1,16 +1,20 @@
 ## 数据结构与算法之美PHP实现
 
 ### 项目运行
-* 依赖composer自动加载，php目录下执行`composer dump-autoload`
+* 依赖composer自动加载，php目录下执行`composer dump-autoload` || `sh buildAutoLoad.sh`
 * 项目代码均在mac&php7环境下跑通
 
 ### 项目实现
-#### 06
+#### 06_linkedlist
 * 单链表php实现
 * 回文判断
-#### 07
+
+#### 07_linkedlist
 * reverse 单链表反转
 * checkCircle 链表中环的检测
 * mergerSortedList 两个有序的链表合并
 * deleteLastKth 删除链表倒数第n个结点
-* findMiddleNode 求链表的中间结点
+* findMiddleNode 求链表的中间结点
+
+#### 08_stack
+* 链栈实现

php/composer.json

@@ -6,7 +6,8 @@
     "autoload": {
         "psr-4": {
             "Algo_06\\": "06_linkedlist/",
-            "Algo_07\\": "07_linkedlist/"
+            "Algo_07\\": "07_linkedlist/",
+            "Algo_08\\": "08_stack/"
         }
     }
 }