原题:
Description
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 Input
10 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
3
Hint
OUTPUT DETAILS:
There are three ponds: one in the upper left, one in the lower left,and one along the right side.
我的代码：
1 #include<iostream>
2 #include<cstdio>
3
4 using namespace std;
5 int flag = 1;
6 char ground[110][110];
7 int tree[110][110];
8 int square = 0;
9 int directionX[8] = {1 , 1 , 1 , 0, 0 , -1, -1 , -1 };
10 int directionY[8] = { 1, 0 , -1, 1, -1, 1, 0, -1 };
11 int n, m;
12
13 void dfs(int i,int j ,int sq)
14 {
15 if (ground[i][j] == ‘W‘&&tree[i][j] == 0)
16 {
17 tree[i][j] = sq;
18 //拓展
19 for (int k = 0; k < 8; k++)
20 {
21 if (i + directionX[k] >= n || j + directionY[k] >= m ||
22 i + directionX[k] < 0 || j + directionY[k] < 0) //越界
23 {continue;}
24 else
25 {
26 dfs(i + directionX[k], j + directionY[k], sq);
27 }
28 }
29 }
30 return;
31 }
32
33
34 int main()
35 {
36
37 cin >> n>>m;
38 for (int i = 0; i < n; i++)
39 scanf("%s", ground[i]);
40 for (int i = 0; i < n; i++)
41 {
42 for (int j = 0; j < m; j++)
43 {
44 if (ground[i][j] == ‘W‘&&tree[i][j] == 0)
45 {
46 dfs(i, j, ++square);
47 }
48 }
49 }
50 cout << square << endl;
51
52 return 0;
53 }