Merge pull request #1398 from fmtvar/0206

添加 (0206.翻转链表.md)：PHP版本

problems/0206.翻转链表.md

@@ -496,8 +496,26 @@ struct ListNode* reverseList(struct ListNode* head){
     return reverse(NULL, head);
 }
 ```
-Scala:
 
+
+
+PHP:
+```php
+// 双指针法：
+function reverseList($head) {
+    $cur = $head;
+    $pre = NULL;
+    while($cur){
+        $temp = $cur->next; 
+        $cur->next = $pre;
+        $pre = $cur;
+        $cur = $temp;
+    }
+    return $pre;
+    }
+```
+
+Scala:
 双指针法：
 ```scala
 object Solution {
@@ -529,6 +547,7 @@ object Solution {
     cur.next = pre
     reverse(cur, tmp)   // 此时cur成为前一个节点，tmp是当前节点
   }
+
 }
 ```
 -----------------------