HDU-1312-Red and Black

HDU-1312-Red and Black

#include <vector>
#include <map>
#include <set>
#include <algorithm>
#include <iostream>
#include <cstdio>
#include <cmath>
#include <cstdlib>
#include <string>
#include <cstring>
using namespace std;
string s[25];
int vis[25][25];
int w,h;
int ans = 0;
void dfs(int c,int r)
{
if (c >= h || c < 0 || r >= w || r < 0) return;
if (vis[c][r] || s[c][r] == '#') return;
vis[c][r] = 1;
ans++;
dfs(c + 1,r);
dfs(c - 1,r);
dfs(c,r + 1);
dfs(c,r - 1);
}
int main(){
while(cin >> w >> h)
{
if (w == 0 && h == 0) break;
int poi = -1,poj = -1;
ans = 0;
memset(vis,0,sizeof(vis));
for (int i = 0; i < h; i++)
{
for (int j = 0; j < w; j++)
{
cin >> s[i][j];
if (s[i][j] == '@') poi = i,poj = j;
}
}
dfs(poi,poj);
cout << ans << endl;
}
return 0;
}