求助60分

#include<bits/stdc++.h>
using namespace std;
char image[10010][10010] , ima[10010][10010];
int n , m , cnt;
void dfs(int a , int b){
	image[a][b] = '.';
	if(a - 1 > 0 and image[a - 1][b] == '#'){
		dfs(a - 1 , b);
	}
	if(a + 1 <= m and image[a + 1][b] == '#'){
		dfs(a + 1 , b);
	}
	if(b + 1 <= n and image[a][b + 1] == '#'){
		dfs(a , b + 1);
	}
	if(b - 1 > 0 and image[a][b - 1] == '#'){ 
		dfs(a , b - 1);
	}
}
void dfs1(int a , int b){
	ima[a][b] = '.';
	if(a - 1 > 0 and ima[a - 1][b] == '#'){
		dfs(a - 1 , b);
	}
	if(a + 1 <= m and ima[a + 1][b] == '#'){
		dfs(a + 1 , b);
	}
	if(b + 1 <= n and ima[a][b + 1] == '#'){
		dfs(a , b + 1);
	}
	if(b - 1 > 0 and ima[a][b - 1] == '#'){ 
		dfs(a , b - 1);
	}
}
int main(){
	cin >> m;
	n = m;
	for(int i = 1; i <= m; i++){
		for(int j = 1; j <= n; j++){
			cin >> image[i][j];
			ima[i][j] = image[i][j];
		}
	}
	for(int i = 1; i <= m; i++){
		for(int j = 1; j <= n; j++){
			if(image[i][j] == '#'){
				cnt++;
				dfs(i , j);
			}
		}
	}
	for(int i = 1; i <= m; i++){
	    for(int j = 1; j <= n; j++){
	        if(ima[i][j] == '.'){
	            image[i][j] = '.';
	        }
	        if(ima[i - 1][j] == '.' or ima[i][j - 1] == '.' or ima[i + 1][j] == '.' or ima[i][j + 1] == '.'){
	            image[i][j] = '.';
	        } else {
	            image[i][j] = '#';
	        }
	    }
	}
	int cnt1 = 0;
	for(int i = 1; i <= m; i++){
		for(int j = 1; j <= n; j++){
			if(image[i][j] == '#'){
				cnt1++;
				dfs1(i , j);
			}
		}
	}
	int ans = cnt - cnt1;
    if(ans < 0) ans = 0;
    cout << ans;
}