给你一个 m x n
的矩阵 board
,由若干字符 'X'
和 'O'
组成,捕获 所有 被围绕的区域:
'O'
的单元格来形成一个区域。'X'
单元格 连接这个区域,并且区域中没有任何单元格位于 board
边缘,则该区域被 'X'
单元格围绕。通过 原地 将输入矩阵中的所有 'O'
替换为 'X'
来 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:
m == board.length
n == board[i].length
1 <= m, n <= 200
board[i][j]
为 'X'
或 'O'