油田（DFS)

//DFS：油田问题
#include <iostream>
using namespace std;
char grid[101][101];
int n,m;

//一个网格的8个方向
int  dir[8][2] = {{-1,-1},{-1,0},{-1,1},{0,-1},{0,1},{1,-1},{1,0},{1,1}};

//从（x,y）进行深度优先遍历
void DFS(int x,int y)
{
    int xx,yy;
    grid [x][y] = '*';
    for (int i = 0; i < 8; i++)
    {
        xx = x + dir[i][0];
        yy = y + dir[i][1];
        if(xx<0 || xx>=n || yy<0 ||yy>=m)
            continue;
        if(grid[xx][yy] =='@')
            DFS(xx,yy);
    }
}

int main()
{
    int i,j;//定义循环变量
    int count;
    while(cin>>n>>m)
    {
        if(n==0 && m ==0)
            break;
        count = 0;

        memset(grid,0,sizeof(grid));

        for(i = 0; i<n; i++)
            cin>>grid[i];

        for(i = 0; i<n; i++)
            for(j = 0; j<m;j++)
                if(grid[i][j]=='@')
                {
                    //在（i,j）遍历，并且遍历了一个“油田”，计数器加1  
                    DFS(i,j);
                    count++;
                }
        cout<<count<<endl;
    }
    return 0;
}