```cpp 题目描述

给定一个二维字符数组  grid ，其中包含  '1' （陆地）和  '0' （水），计算岛屿的数量。岛屿被水包围，并且通过水平或垂直方向上相邻的陆地连接而成。你可以假设网格的四个边均被水包围。

示例 1：

plaintext

输入：grid = [ ["1","1","1","1","0"], ["1","1","0","1","0"], ["1","1","0","0","0"], ["0","0","0","0","0"] ] 输出：1  

示例 2：

plaintext

输入：grid = [ ["1","1","0","0","0"], ["1","1","0","0","0"], ["0","0","1","0","0"], ["0","0","0","1","1"] ] 输出：3