Nav: << previous: 129.求根节点到叶节点数字之和 | next: 131.分割回文串 >>
Description
tab: English
<p>You are given an <code>m x n</code> matrix <code>board</code> containing <strong>letters</strong> <code>'X'</code> and <code>'O'</code>, <strong>capture regions</strong> that are <strong>surrounded</strong>:</p>
<ul>
<li><strong>Connect</strong>: A cell is connected to adjacent cells horizontally or vertically.</li>
<li><strong>Region</strong>: To form a region <strong>connect every</strong> <code>'O'</code> cell.</li>
<li><strong>Surround</strong>: The region is surrounded with <code>'X'</code> cells if you can <strong>connect the region </strong>with <code>'X'</code> cells and none of the region cells are on the edge of the <code>board</code>.</li>
</ul>
<p>To capture a <strong>surrounded region</strong>, replace all <code>'O'</code>s with <code>'X'</code>s <strong>in-place</strong> within the original board. You do not need to return anything.</p>
<p> </p>
<p><strong class="example">Example 1:</strong></p>
<div class="example-block">
<p><strong>Input:</strong> <span class="example-io">board = [["X","X","X","X"],["X","O","O","X"],["X","X","O","X"],["X","O","X","X"]]</span></p>
<p><strong>Output:</strong> <span class="example-io">[["X","X","X","X"],["X","X","X","X"],["X","X","X","X"],["X","O","X","X"]]</span></p>
<p><strong>Explanation:</strong></p>
<img alt="" src="https://assets.leetcode.com/uploads/2021/02/19/xogrid.jpg" style="width: 367px; height: 158px;" />
<p>In the above diagram, the bottom region is not captured because it is on the edge of the board and cannot be surrounded.</p>
</div>
<p><strong class="example">Example 2:</strong></p>
<div class="example-block">
<p><strong>Input:</strong> <span class="example-io">board = [["X"]]</span></p>
<p><strong>Output:</strong> <span class="example-io">[["X"]]</span></p>
</div>
<p> </p>
<p><strong>Constraints:</strong></p>
<ul>
<li><code>m == board.length</code></li>
<li><code>n == board[i].length</code></li>
<li><code>1 <= m, n <= 200</code></li>
<li><code>board[i][j]</code> is <code>'X'</code> or <code>'O'</code>.</li>
</ul>
---
[submissions](https://leetcode.com/problems/surrounded-regions/submissions/) | [solutions](https://leetcode.com/problems/surrounded-regions/solutions/)
tab: 中文
<p>给你一个 <code>m x n</code> 的矩阵 <code>board</code> ，由若干字符 <code>'X'</code> 和 <code>'O'</code> 组成，<strong>捕获</strong> 所有 <strong>被围绕的区域</strong>：</p>
<ul>
<li><strong>连接：</strong>一个单元格与水平或垂直方向上相邻的单元格连接。</li>
<li><strong>区域：连接所有 </strong><code>'O'</code> 的单元格来形成一个区域。</li>
<li><strong>围绕：</strong>如果您可以用 <code>'X'</code> 单元格 <strong>连接这个区域</strong>，并且区域中没有任何单元格位于 <code>board</code> 边缘，则该区域被 <code>'X'</code> 单元格围绕。</li>
</ul>
<p>通过 <strong>原地</strong> 将输入矩阵中的所有 <code>'O'</code> 替换为 <code>'X'</code> 来 <strong>捕获被围绕的区域</strong>。你不需要返回任何值。</p>
<div class="original__bRMd">
<div>
<p> </p>
<p><strong class="example">示例 1：</strong></p>
<div class="example-block">
<p><strong>输入：</strong><span class="example-io">board = [['X','X','X','X'],['X','O','O','X'],['X','X','O','X'],['X','O','X','X']]</span></p>
<p><b>输出：</b><span class="example-io">[['X','X','X','X'],['X','X','X','X'],['X','X','X','X'],['X','O','X','X']]</span></p>
<p><strong>解释：</strong></p>
<img alt="" src="https://pic.leetcode.cn/1718167191-XNjUTG-image.png" style="width: 367px; height: 158px;" />
<p>在上图中，底部的区域没有被捕获，因为它在 board 的边缘并且不能被围绕。</p>
</div>
<p><strong class="example">示例 2：</strong></p>
<div class="example-block">
<p><strong>输入：</strong><span class="example-io">board = [['X']]</span></p>
<p><strong>输出：</strong><span class="example-io">[['X']]</span></p>
</div>
<p> </p>
<p><strong>提示：</strong></p>
<ul>
<li><code>m == board.length</code></li>
<li><code>n == board[i].length</code></li>
<li><code>1 <= m, n <= 200</code></li>
<li><code>board[i][j]</code> 为 <code>'X'</code> 或 <code>'O'</code></li>
</ul>
</div>
</div>
---
[提交记录](https://leetcode.cn/problems/surrounded-regions/submissions/) | [题解](https://leetcode.cn/problems/surrounded-regions/solution/)
Solutions & Notes
properties:
note.updated:
displayName: Last Updated
note.relative_links:
displayName: Related Links
note.desc:
displayName: Description
note.grade:
displayName: Rating
note.program_language:
displayName: Language
note.time_complexity:
displayName: TC
note.space_complexity:
displayName: SC
views:
- type: table
name: Solutions & Notes
filters:
and:
- file.hasLink(this.file)
- file.tags.containsAny("leetcode/solution", "leetcode/note")
order:
- file.name
- desc
- program_language
- time_complexity
- space_complexity
- grade
- relative_links
- updated
sort:
- property: grade
direction: ASC
- property: time_complexity
direction: ASC
- property: program_language
direction: ASC
columnSize:
file.name: 104
note.space_complexity: 65
note.grade: 126
Similar Problems
properties:
note.lcTopics:
displayName: Topics
note.lcAcRate:
displayName: AC Rate
note.favorites:
displayName: Favorites
note.grade:
displayName: Rating
note.translatedTitle:
displayName: Title (CN)
note.lcDifficulty:
displayName: Difficulty
views:
- type: table
name: Similar Problems
filters:
and:
- file.hasLink(this.file)
- similarQuestions.contains(this.file)
order:
- file.name
- translatedTitle
- lcTopics
- lcDifficulty
- lcAcRate
- grade
- favorites
sort:
- property: file.name
direction: ASC
- property: lcTopics
direction: DESC
columnSize:
note.translatedTitle: 240
note.lcTopics: 347
note.lcAcRate: 75
note.grade: 122