1818:红与黑

1818:红与黑

题目链接http://noi.openjudge.cn/ch0205/1818/

#include<iostream>
#include<cstring>
using namespace std;
char a[25][25];
bool vis[25][25] = {
    
     0 };
int maxx = 0;
int w, h;
bool fw(int x, int y) {
    
    
	if (x >= 1 && x <= h && y >= 1 && y <= w)
		return true;
	return false;
}
void dfs(int x, int y) {
    
    
	vis[x][y] = 1;
	maxx++;
	if (fw(x-1,y)&&a[x - 1][y] == '.' && vis[x - 1][y] == 0) {
    
    
		dfs(x - 1, y);
	}
	if (fw(x + 1, y) && a[x + 1][y] == '.' && vis[x + 1][y] == 0) {
    
    
		dfs(x + 1, y);
	}
	if (fw(x , y - 1) && a[x ][y-1] == '.' && vis[x ][y - 1] == 0) {
    
    
		dfs(x , y - 1);
	}
	if (fw(x , y+1) && a[x ][y+1] == '.' && vis[x ][y+1] == 0) {
    
    
		dfs(x , y+1);
	}
}
int main() {
    
    
	
	while (cin >> w >> h) {
    
    
		if (w == 0 && h == 0)
			break;
		int x, y;
		for (int i = 1; i <= h; i++) {
    
    
			for (int j = 1; j <= w; j++) {
    
    
				cin >> a[i][j];
				if (a[i][j] == '@')
				{
    
    
					x = i, y = j;
				}
			}
		}
		maxx = 0;
		memset(vis, 0, sizeof(vis));
		dfs(x, y);
		cout << maxx << endl;
	}
	return 0;
}