题目连接

http://acm.hdu.edu.cn/showproblem.php?pid=2952

Counting Sheep

Description

A while ago I had trouble sleeping. I used to lie awake, staring at the ceiling, for hours and hours. Then one day my grandmother suggested I tried counting sheep after I‘d gone to bed. As always when my grandmother suggests things, I decided to try it out. The only problem was, there were no sheep around to be counted when I went to bed.

Creative as I am, that wasn‘t going to stop me. I sat down and wrote a computer program that made a grid of characters, where # represents a sheep, while . is grass (or whatever you like, just not sheep). To make the counting a little more interesting, I also decided I wanted to count flocks of sheep instead of single sheep. Two sheep are in the same flock if they share a common side (up, down, right or left). Also, if sheep A is in the same flock as sheep B, and sheep B is in the same flock as sheep C, then sheeps A and C are in the same flock.

Now, I‘ve got a new problem. Though counting these sheep actually helps me fall asleep, I find that it is extremely boring. To solve this, I‘ve decided I need another computer program that does the counting for me. Then I‘ll be able to just start both these programs before I go to bed, and I‘ll sleep tight until the morning without any disturbances. I need you to write this program for me.

Input

The first line of input contains a single number T, the number of test cases to follow.

Each test case begins with a line containing two numbers, H and W, the height and width of the sheep grid. Then follows H lines, each containing W characters (either # or .), describing that part of the grid.

Output

For each test case, output a line containing a single number, the amount of sheep flock son that grid according to the rules stated in the problem description.

Notes and Constraints
0 < T <= 100
0 < H,W <= 100

Sample Input

2
4 4
#.#.
.#.#
#.##
.#.#
3 5
###.#
..#..
#.###

Sample Output

6
3

dfs求连通块个数。。

 1 #include<algorithm>
 2 #include<iostream>
 3 #include<cstdlib>
 4 #include<cstring>
 5 #include<cstdio>
 6 #include<vector>
 7 #include<map>
 8 using std::cin;
 9 using std::cout;
10 using std::endl;
11 using std::find;
12 using std::sort;
13 using std::map;
14 using std::pair;
15 using std::vector;
16 using std::multimap;
17 #define pb(e) push_back(e)
18 #define sz(c) (int)(c).size()
19 #define mp(a, b) make_pair(a, b)
20 #define all(c) (c).begin(), (c).end()
21 #define iter(c) decltype((c).begin())
22 #define cls(arr,val) memset(arr,val,sizeof(arr))
23 #define cpresent(c, e) (find(all(c), (e)) != (c).end())
24 #define rep(i, n) for (int i = 0; i < (int)(n); i++)
25 #define tr(c, i) for (iter(c) i = (c).begin(); i != (c).end(); ++i)
26 const int N = 110;
27 typedef unsigned long long ull;
28 char G[N][N];
29 bool vis[N][N];
30 int H, W;
31 const int dx[] = { 0, 0, -1, 1 }, dy[] = { -1, 1, 0, 0 };
32 void dfs(int x, int y) {
33     vis[x][y] = true;
34     rep(i, 4) {
35         int nx = x + dx[i], ny = y + dy[i];
36         if (nx < 0 || nx >= H || ny < 0 || ny >= W) continue;
37         if (vis[nx][ny] || G[nx][ny] == ‘.‘) continue;
38         dfs(nx, ny);
39     }
40 }
41 int main() {
42 #ifdef LOCAL
43     freopen("in.txt", "r", stdin);
44     freopen("out.txt", "w+", stdout);
45 #endif
46     int t, ans;
47     scanf("%d", &t);
48     while (t--) {
49         ans = 0;
50         cls(vis, false);
51         scanf("%d %d", &H, &W);
52         rep(i, H) scanf("%s", G[i]);
53         rep(i, H) {
54             rep(j, W) {
55                 if (!vis[i][j] && G[i][j] == ‘#‘) ans++, dfs(i, j);
56             }
57         }
58         printf("%d\n", ans);
59     }
60     return 0;
61 }