# 力扣200. 岛屿数量


## 力扣200. Number of Islands（岛屿数量）

给你一个由 '1'（陆地）和 '0'（水）组成的二维网格，请你计算网格中岛屿的数量。岛屿总是被水包围，并且每座岛屿只能由水平方向和竖直方向上相邻的陆地连接形成。

示例 1：

![](../posts/01_学习/87_LeetCode/0200_岛屿数量/img/0200-1-description.png)

```
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：

![](../posts/01_学习/87_LeetCode/0200_岛屿数量/img/0200-2-description.png)

```
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
```

提示：
- m == grid.length
- n == grid[i].length
- 1 <= m, n <= 300
- grid[i][j] 的值为 '0' 或 '1'