POJ 2386 Lake Counting dfs

#include <iostream> 
using namespace std;
typedef long long ll;

char a[110][110];
    int m,n;
void dfs(int x ,int y){
    if(x < 0||x >= n||y < 0||y >= m){
        return;
    }
    a[x][y] = ‘.‘;
    
    for(int i = -1;i <= 1; i++){
        for(int j = -1;j <= 1; j++){
            if(a[x+i][y+j] == ‘W‘){
                dfs(x+i,y+j);
            }
        }
    }
    return;
}


int main() {
     int ans = 0;
 
  cin >> n >> m;
  for(int i = 0;i < n; i++){
      for(int j = 0;j < m; j++){
          cin >> a[i][j];
        }
    }
    
    for(int i = 0;i < n; i++){
        for(int j = 0;j < m; j++){
            if(a[i][j] == ‘W‘){
                dfs(i,j);
                ans++;
            }
        }
    }
    cout << ans << endl;
  return 0;
}
//  writen by zhangjiuding