求连通域个数，简单题

1 #include 
     
       2 using namespace std; 3 const int INF = 0x3f3f3f3f; 4 typedef long long LL; 5 int n,m,ans=0; 6 char s[1001][1001]; 7 void dfs(int x,int y) 8 { 9     if(x<0||x>=n||y<0||y>=m||s[x][y]=='.')return;10     s[x][y]='.';11     dfs(x,y+1);12     dfs(x,y-1);13     dfs(x+1,y);14     dfs(x-1,y);15     dfs(x+1,y+1);16     dfs(x+1,y-1);17     dfs(x-1,y+1);18     dfs(x-1,y-1);19 }20 int main()21 {22     cin>>n>>m;23     for(int i=0;i