ZOJ 2412 Farm Irrigation(DFS 条件通讯块)

意甲冠军  两个农田管内可直接连接到壳体  他们将能够共享一个水源   有11种农田  管道的位置高于一定  一个农田矩阵  问至少须要多少水源

DFS的连通块问题  两个相邻农田的管道能够直接连接的话他们就属于一个连通块  题目就是求连通块个数

#include<cstdio>
#include<cstring>
using namespace std;
const int N = 55;
char mat[N][N];
int type[11][4] = {   //相应11种水管类型 按顺时针方向有管道的为1否则为0
    {1, 0, 0, 1}, {1, 1, 0, 0}, {0, 0, 1, 1}, {0, 1, 1, 0},
    {1, 0, 1, 0}, {0, 1, 0, 1}, {1, 1, 0, 1}, {1, 0, 1, 1},
    {0, 1, 1, 1}, {1, 1, 1, 0}, {1, 1, 1, 1}
};

int dfs(int r, int c)
{
    int cur = mat[r][c] - 'A';
    if(cur < 0 || cur > 10) return 0;
    mat[r][c] = 0;           //标记已经訪问 0-'A'是小于0的
    int up = mat[r - 1][c] - 'A', dw = mat[r + 1][c] - 'A',
        le = mat[r][c - 1] - 'A', ri = mat[r][c + 1] - 'A';  //4个相邻块的管道类型
    if(up > -1 && up < 11 && type[up][2] && type[cur][0])  dfs(r - 1, c);
    if(dw > -1 && dw < 11 && type[dw][0] && type[cur][2])  dfs(r + 1, c);
    if(le > -1 && le < 11 && type[le][1] && type[cur][3])  dfs(r, c - 1);
    if(ri > -1 && ri < 11 && type[ri][3] && type[cur][1])  dfs(r, c + 1);
    return 1;     //一个连通块中仅仅有一个返回1
}

int main()
{
    int n, m, ans;
    while (scanf("%d%d", &n, &m), n >= 0)
    {
        ans = 0;
        memset(mat, 0, sizeof(mat));
        for(int i = 1; i <= n; ++i)
            scanf("%s", mat[i] + 1);
        for(int i = 1; i <= n; ++i)
            for(int j = 1; j <= m; ++j)
                ans += dfs(i, j);
        printf("%d\n", ans);
    }
    return 0;
}

Farm Irrigation

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Time Limit: 2 Seconds      Memory Limit: 65536 KB

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Benny has a spacious farm land to irrigate. The farm land is a rectangle, and is divided into a lot of samll squares. Water pipes are placed in these squares. Different square has a different
type of pipe. There are 11 types of pipes, which is marked from A to K, as Figure 1 shows.

name=0000%2F2412%2F1.gif" alt="">

Figure 1

Benny has a map of his farm, which is an array of marks denoting the distribution of water pipes over the whole farm. For example, if he has a map

ADC
FJK
IHE

then the water pipes are distributed like

name=0000%2F2412%2F2.gif" alt="">

Figure 2

Several wellsprings are found in the center of some squares, so water can flow along the pipes from one square to another. If water flow crosses one square, the whole farm land in this square
is irrigated and will have a good harvest in autumn.

Now Benny wants to know at least how many wellsprings should be found to have the whole farm land irrigated. Can you help him?

Note: In the above example, at least 3 wellsprings are needed, as those red points in Figure 2 show.

Input

There are several test cases! In each test case, the first line contains 2 integers M and N, then M lines follow. In each of these lines, there are N characters, in the range of 'A' to 'K', denoting
the type of water pipe over the corresponding square. A negative M or N denotes the end of input, else you can assume 1 <= M, N <= 50.

Output

For each test case, output in one line the least number of wellsprings needed.

Sample Input

2 2
DK
HF

3 3
ADC
FJK
IHE

-1 -1

Sample Output

2
3

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