题解 | 没挡住洪水

#include <iostream>
#include <string>
#include <queue>
#include <algorithm>

using namespace std;

struct Grid {
	int x;
	int y;
};

int n, m, ans;
int direction[4][2] = {{1, 0}, {-1, 0}, {0, 1}, {0, -1}};
char c[1005][1005];
int vis[1005][1005];

//题目是描述不清的，样例是懒得写的，想通过是得看别人题解的
int main() {
	cin >> n;
	m = n;
	cin.ignore();
	for (int i = 0; i < n; i++) {
		cin.getline(c[i], m + 1);
	}
	for(int i = 0; i < n; i++) {
		for(int j = 0;  j < m; j++) {
			if (!vis[i][j] && c[i][j] == '#') {
				vector<Grid> v;
				bool safe = false;
				queue<Grid> q;				 
				Grid st;
				st.x = i;
				st.y = j;
				q.push(st);
				vis[st.x][st.y] = 1;
				while (!q.empty()) {
					Grid g = q.front();
					q.pop();
					bool flag = true;
//					if (g.x == 0 || g.y == 0 || g.x == n - 1 || g.y == m - 1) flag = false;
//					cnt++;
					for (int k = 0; k < 4; k++) {
						int x = g.x + direction[k][0];
						int y = g.y + direction[k][1];
						if (x > -1 && x < n && y > -1 && y < m && c[x][y] == '#') {
							if(!vis[x][y]) {
								vis[x][y] = 1;
								Grid new_grid;
								new_grid.x = x;
								new_grid.y = y;
								q.push(new_grid);
								v.push_back(new_grid);	
							}
						} else {
							flag = false;
						} 
					}
					safe |= flag;
				}
				ans += safe ? 0 : 1; 
			}
  		}
	}
	cout << ans << endl;
}