# 题目

Due to recent rains, water has pooled in various places in Farmer John’s field, which is represented by a rectangle of N x M (1 <= N <= 100; 1 <= M <= 100) squares. Each square contains either water (‘W’) or dry land (‘.’). Farmer John would like to figure out how many ponds have formed in his field. A pond is a connected set of squares with water in them, where a square is considered adjacent to all eight of its neighbors.

Given a diagram of Farmer John’s field, determine how many ponds he has.

Input

Line 1: Two space-separated integers: N and M

Lines 2..N+1: M characters per line representing one row of Farmer John’s field. Each character is either ‘W’ or ‘.’. The characters do not have spaces between them.

Output- Line 1: The number of ponds in Farmer John’s field.

Sample Input1

2

3

4

5

6

7

8

9

10

1110 12

W........WW.

.WWW.....WWW

....WW...WW.

.........WW.

.........W..

..W......W..

.W.W.....WW.

W.W.W.....W.

.W.W......W.

..W.......W.

Sample Output

1 | 3 |

`Hint`

OUTPUT DETAILS:

There are three ponds: one in the upper left, one in the lower left,and one along the right side.

# 思路

dfs算法的简单应用。

对整张图来说

**W**，这水池数加1，同时将它改为

**.**

**W**为起点，搜索与它相连的位置，若发现

**W**，则将它改为

**.**，然后又搜索这个点周围的位置

# 代码

1 | #include<iostream> |