UVA 572 (dfs)

题意：找出一块地有多少油田。‘@’表示油田。找到一块就全部标记。

#include<cstdio>

#define maxn 110

char s[maxn][maxn];
int n,m;
int ans;
int dir[][] = {{-,-},{-,},{-,},{,},{,},{,},{,-},{,-}};

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

int main()
{
    //freopen("in.txt","r",stdin);
    while(scanf("%d%d",&m,&n) != EOF){
        ans = ;
        if(m ==  && n == )
            break;
        for(int i = ;i < m; i++)
            scanf("%s",s[i]);
        for(int i = ;i < m; i++){
            for(int j = ;j < n; j++){
                if(s[i][j] == '@'){
                    dfs(i,j);
                    ans++;
                }
            }
        }
        printf("%d\n",ans);
    }
    return ;
}