update exercises

data/2.算法中阶/6.leetcode-双指针/4.142-环形链表 II/solution.md

@@ -16,7 +16,7 @@
 
 <p><strong>示例 1：</strong></p>
 
-<p><img alt="" src="https://assets.leetcode-cn.com/aliyun-lc-upload/uploads/2018/12/07/circularlinkedlist.png" style="height: 97px; width: 300px;" /></p>
+<p><img src="https://assets.leetcode-cn.com/aliyun-lc-upload/uploads/2018/12/07/circularlinkedlist.png" style="height: 97px; width: 300px;" /></p>
 
 <pre>
 <strong>输入：</strong>head = [3,2,0,-4], pos = 1
@@ -28,7 +28,7 @@
 
 <p><strong>示例 2：</strong></p>
 
-<p><img alt="" src="https://assets.leetcode-cn.com/aliyun-lc-upload/uploads/2018/12/07/circularlinkedlist_test2.png" style="height: 74px; width: 141px;" /></p>
+<p><img src="https://assets.leetcode-cn.com/aliyun-lc-upload/uploads/2018/12/07/circularlinkedlist_test2.png" style="height: 74px; width: 141px;" /></p>
 
 <pre>
 <strong>输入：</strong>head = [1,2], pos = 0

data/2.算法中阶/6.leetcode-双指针/5.141-环形链表/solution.md

@@ -16,7 +16,7 @@
 
 <p><strong>示例 1：</strong></p>
 
-![](https://assets.leetcode-cn.com/aliyun-lc-upload/uploads/2018/12/07/circularlinkedlist.png)
+<p><img alt="" src="https://assets.leetcode-cn.com/aliyun-lc-upload/uploads/2018/12/07/circularlinkedlist.png" style="height: 97px; width: 300px;"></p>
 
 <pre><strong>输入：</strong>head = [3,2,0,-4], pos = 1