Merge pull request wangzheng0822#65 from Hkesd/master

php 09_queue

php/09_queue/QueueOnLinkedList.php

@@ -0,0 +1,115 @@
+<?php
+/**
+ * User: Hkesd
+ * Date: 2018/10/13 11:26
+ * Desc:
+ */
+
+namespace Algo_09;
+
+use Algo_06\SingleLinkedListNode;
+
+/**
+ * 队列 链表实现
+ *
+ * Class QueueOnLinkedList
+ */
+class QueueOnLinkedList
+{
+    /**
+     * 队列头节点
+     *
+     * @var SingleLinkedListNode
+     */
+    public $head;
+
+    /**
+     * 队列尾节点
+     *
+     * @var null
+     */
+    public $tail;
+
+    /**
+     * 队列长度
+     *
+     * @var int
+     */
+    public $length;
+
+    /**
+     * QueueOnLinkedList constructor.
+     */
+    public function __construct()
+    {
+        $this->head = new SingleLinkedListNode();
+        $this->tail = $this->head;
+
+        $this->length = 0;
+    }
+
+    /**
+     * 入队
+     *
+     * @param $data
+     */
+    public function enqueue($data)
+    {
+        $newNode = new SingleLinkedListNode();
+        $newNode->data = $data;
+
+        $this->tail->next = $newNode;
+        $this->tail = $newNode;
+
+        $this->length++;
+    }
+
+    /**
+     * 出队
+     *
+     * @return SingleLinkedListNode|bool|null
+     */
+    public function dequeue()
+    {
+        if (0 == $this->length) {
+            return false;
+        }
+
+        $node = $this->head->next;
+        $this->head->next = $this->head->next->next;
+
+        $this->length--;
+
+        return $node;
+    }
+
+    /**
+     * 获取队列长度
+     *
+     * @return int
+     */
+    public function getLength()
+    {
+        return $this->length;
+    }
+
+    /**
+     * 打印队列
+     */
+    public function printSelf()
+    {
+        if (0 == $this->length) {
+            echo 'empty queue' . PHP_EOL;
+            return;
+        }
+
+        echo 'head.next -> ';
+        $curNode = $this->head;
+        while ($curNode->next) {
+            echo $curNode->next->data . ' -> ';
+
+            $curNode = $curNode->next;
+        }
+        echo 'NULL' . PHP_EOL;
+    }
+}

php/09_queue/main.php

@@ -0,0 +1,29 @@
+<?php
+/**
+ * User: Hkesd
+ * Date: 2018/10/13 11:46
+ * Desc:
+ */
+
+namespace Algo_09;
+
+require_once "../vendor/autoload.php";
+
+$queue = new QueueOnLinkedList();
+$queue->enqueue(1);
+$queue->enqueue(2);
+$queue->enqueue(3);
+$queue->enqueue(4);
+$queue->enqueue(5);
+$queue->printSelf();
+var_dump($queue->getLength());
+
+$queue->dequeue();
+$queue->printSelf();
+$queue->dequeue();
+$queue->dequeue();
+$queue->dequeue();
+$queue->printSelf();
+
+$queue->dequeue();
+$queue->printSelf();

php/README.md

@@ -17,4 +17,7 @@
 * findMiddleNode 求链表的中间结点
 
 #### 08_stack
-* 链栈实现
+* 链栈实现
+
+#### 09_stack
+* 队列链表实现

php/composer.json

@@ -7,7 +7,8 @@
         "psr-4": {
             "Algo_06\\": "06_linkedlist/",
             "Algo_07\\": "07_linkedlist/",
-            "Algo_08\\": "08_stack/"
+            "Algo_08\\": "08_stack/",
+            "Algo_09\\": "09_queue/"
         }
     }
 }