hdu 2952 Counting Sheep

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 }

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