hdu 1241 (Oil Deposits) legendary dfs

Problem link adress:http://acm.hdu.edu.cn/showproblem.php?pid=1241

These days I have encountered some problems when I was doing the searching problems;

May those problem need to use the DFS algorithm!  So I started to learning the DFS:

Lots of friends says this probelm is a simple DFS problem, so I have a try on the problem!

Of course, I learned a lot from the "simple" problem!

#include<iostream>
#include<cstring>
#include<queue>
#include<cstdio>
using namespace std;
int mark[111][111];
char map[105][105];
int m,n;
int dir[8][2]={0,1,0,-1,1,0,-1,0,1,-1,-1,1,1,1,-1,-1};
void DFS(int a,int b)
{
    int x,y;
    for(int i=0;i<8;i++)
    {
        x=a+dir[i][0];
        y=b+dir[i][1];
        if(x>=0&&x<m&&y>=0&&y<n&&mark[x][y]==0&&map[x][y]=='@')
        {
            mark[x][y]=1;
            DFS(x,y);
        }
    }
}


int main()
{
    int i,j;
    while(cin>>m>>n)
    {
        getchar();
        if(m==0) break;
        for(i=0;i<m;i++)
          for(j=0;j<n;j++)
              cin>>map[i][j];
        memset(mark,0,sizeof(mark));
        int sum;
        sum=0;
        for(i=0;i<m;i++)
            for(j=0;j<n;j++)
            {
                if(map[i][j]=='@'&&mark[i][j]==0)
                {
                    sum++;
                    mark[i][j]=1;
                    DFS(i,j);
                }
            }
            cout<<sum<<endl;
    }
    return 0;
}