最簡單的板子題，摸清dfs套路就好，不用剪枝，不用優化，dfs的模板在我部落格的搜尋模組裡找。

#include <iostream>
#include <cstring>
#include <ctime>

using namespace std;

const int maxn = 105;

int ans;
int n, m;
char Map[maxn][maxn];

int a[] = {1, -1, 0, 0, 1, 1, -1, -1};
int b[] = {0, 0, 1, -1, 1, -1, 1, -1};

void dfs(int x, int y)
{
    Map[x][y] = '*';
    for (int i = 0; i < 8; i++) {
        int xx = x+a[i];
        int yy = y+b[i];
        if (xx >= 0 && xx < n && yy >= 0 && yy < m && Map[xx][yy] == '@') dfs(xx, yy);
    }
}

int main()
{
    ios::sync_with_stdio(false);

    while (cin >> n >> m) {
        if (!n && !m) break;
        for (int i = 0; i < n; i++) for (int j = 0; j < m; j++) cin >> Map[i][j];
        ans = 0;
        for (int i = 0;i < n; i++) {
            for (int j = 0; j < m; j++) {
                if (Map[i][j] == '@') {ans++; dfs(i, j);}
            }
        }
        cout << ans << endl;
    }
    return 0;
}