给你一个 m x n 的矩阵 board ,由若干字符 'X''O' 组成,捕获 所有 被围绕的区域

通过 原地 将输入矩阵中的所有 'O' 替换为 'X'捕获被围绕的区域。你不需要返回任何值。

 

示例 1:

输入:board = [["X","X","X","X"],["X","O","O","X"],["X","X","O","X"],["X","O","X","X"]]

输出:[["X","X","X","X"],["X","X","X","X"],["X","X","X","X"],["X","O","X","X"]]

解释:

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。

示例 2:

输入:board = [["X"]]

输出:[["X"]]

 

提示: