# Number of Islands

Given a two-dimensional integer `matrix`

of 1s and 0s, return the number of “islands” in the matrix. A `1`

represents land and `0`

represents water, so an island is a group of 1s that are neighboring whose perimeter is surrounded by water.

Note: Neighbors can only be directly horizontal or vertical, not diagonal.

**Constraints**

`n, m ≤ 100`

where`n`

and`m`

are the number of rows and columns in`matrix`

.

https://binarysearch.com/problems/Number-of-Islands

## Examples

### Example 1

**Input**

- matrix =

```
[[1,1],
[1,0]]
```

**Output**

- answer =
`1`

### Example 2

**Input**

- matrix =

```
[[0,1],
[1,0]]
```

**Output**

- answer =
`2`

### Example 3

**Input**

- matrix =

```
[[1,0,0,0,0],
[0,0,1,1,0],
[0,1,1,0,0],
[0,0,0,0,0],
[1,1,0,0,1],
[1,1,0,0,1]]
```

**Output**

- answer =
`4`

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