存量题库数据更新

leetcode/problem/surrounded-regions.html

@@ -3,15 +3,19 @@
 <p>A region is <strong>captured</strong> by flipping all <code>&#39;O&#39;</code>s into <code>&#39;X&#39;</code>s in that surrounded region.</p>
 
 <p>&nbsp;</p>
-<p><strong>Example 1:</strong></p>
+<p><strong class="example">Example 1:</strong></p>
 <img alt="" src="https://assets.leetcode.com/uploads/2021/02/19/xogrid.jpg" style="width: 550px; height: 237px;" />
 <pre>
 <strong>Input:</strong> board = [[&quot;X&quot;,&quot;X&quot;,&quot;X&quot;,&quot;X&quot;],[&quot;X&quot;,&quot;O&quot;,&quot;O&quot;,&quot;X&quot;],[&quot;X&quot;,&quot;X&quot;,&quot;O&quot;,&quot;X&quot;],[&quot;X&quot;,&quot;O&quot;,&quot;X&quot;,&quot;X&quot;]]
 <strong>Output:</strong> [[&quot;X&quot;,&quot;X&quot;,&quot;X&quot;,&quot;X&quot;],[&quot;X&quot;,&quot;X&quot;,&quot;X&quot;,&quot;X&quot;],[&quot;X&quot;,&quot;X&quot;,&quot;X&quot;,&quot;X&quot;],[&quot;X&quot;,&quot;O&quot;,&quot;X&quot;,&quot;X&quot;]]
-<strong>Explanation:</strong> Surrounded regions should not be on the border, which means that any &#39;O&#39; on the border of the board are not flipped to &#39;X&#39;. Any &#39;O&#39; that is not on the border and it is not connected to an &#39;O&#39; on the border will be flipped to &#39;X&#39;. Two cells are connected if they are adjacent cells connected horizontally or vertically.
+<strong>Explanation:</strong> Notice that an &#39;O&#39; should not be flipped if:
+- It is on the border, or
+- It is adjacent to an &#39;O&#39; that should not be flipped.
+The bottom &#39;O&#39; is on the border, so it is not flipped.
+The other three &#39;O&#39; form a surrounded region, so they are flipped.
 </pre>
 
-<p><strong>Example 2:</strong></p>
+<p><strong class="example">Example 2:</strong></p>
 
 <pre>
 <strong>Input:</strong> board = [[&quot;X&quot;]]