HDU 1241 dfs入门练手题

// Problem: Oil Deposits
// Contest: HDOJ
// URL: http://acm.hdu.edu.cn/showproblem.php?pid=1241
// Memory Limit: 65 MB
// Time Limit: 2000 ms
//
// Powered by CP Editor (https://cpeditor.org)

#include 

using namespace std;

const int N = 105;
int n, m;
char a[N][N];
int dir[8][2] = {{1, 0}, {-1, 0}, {1, 1}, {1, -1}, {-1, -1}, {-1, 1}, {0, 1}, {0, -1}};
bool ok(int x, int y)
{
    if (x < 1 || x > n || y < 1 || y > m)
        return false;
    return true;
}
void dfs(int x, int y)
{
    a[x][y] = '*';
    for (int i = 0; i < 8; i++)
    {
        x += dir[i][0];
        y += dir[i][1];
        if (ok(x, y) && a[x][y] == '@')
        {
            dfs(x, y);
        }
    }
}

int main()
{
    while (cin >> n >> m, n)
    {
        for (int i = 1; i <= n; i++)
        {
            for (int j = 1; j <= m; j++)
            {
                cin >> a[i][j];
            }
            getchar();
        }
        int count = 0;
        for (int i = 1; i <= n; i++)
        {
            for (int j = 1; j <= m; j++)
            {
                if (a[i][j] == '@')
                {
                    dfs(i, j);
                    count++;
                }
            }
        }
        printf("%dn", count);
    }
}