HDU 1241 Oil Deposits --- 入门DFS

题目链接： http://acm.hdu.edu.cn/showproblem.php?pid=1241

/* HDU 1241 Oil Deposits --- 入门DFS */
#include <cstdio>

int m, n; //n行m列
char mapp[105][105];

/* 将和i,j同处于一个连通块的字符标记出来 */
void dfs(int i, int j){
    if (i < 0 || j < 0 || i >= n || j >= m || mapp[i][j] != ‘@‘)
        return;
    //此处直接更改为*,省去了一个标记数组,当然也可以用一个标记数组visit记录访问状态
    mapp[i][j] = ‘*‘; 

    for (int dr = -1; dr <= 1; dr++)   //递归遍历8个方向
        for (int dc = -1; dc <= 1; dc++)
        {
            if (dr != 0 || dc != 0)
                dfs(i + dr, j + dc);
        }
}

int main()
{
    int cnt;

    while (scanf("%d%d", &n, &m) && n != 0){
        getchar();
        for (int i = 0; i < n; ++i)
        {
            gets(mapp[i]);
        }

        cnt = 0;
        for (int i = 0; i < n; ++i)
        {
            for (int j = 0; j < m; ++j)
            {
                if (mapp[i][j] == ‘@‘){
                    ++cnt;
                    dfs(i, j); //调用一次就是一个连通块全部标记成*
                }
            }
        }
        printf("%d\n", cnt);
    }

    return 0;
}