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.lengthn == board[i].length1 <= m, n <= 200board[i][j]为'X'或'O'