Red and Black---POJ - 1979

 1 #include<iostream>
 2 #include<cstring>
 3 #include<cstdio>
 4 #include<algorithm>
 5 using namespace std;
 6 int n,m;
 7 int ans=0;
 8 int vis[30][30];
 9 char title[30][30];
10 int fx[4]={-1,0,1,0},fy[4]={0,1,0,-1};
11 
12 void dfs(int x,int y){
13     ans++;
14     vis[x][y]=1;
15     for(int i=0; i<4; i++ ){
16         int nx=x+fx[i];
17         int ny=y+fy[i];
18         if(nx>=0&&nx<n&&ny>=0&&ny<m&&title[nx][ny]==‘.‘&&!vis[nx][ny]){
19             dfs(nx,ny);
20         }
21     }
22 }
23 
24 int main(){
25     while(~scanf("%d%d",&m,&n)&&n&&m){
26 //        getchar();
27         ans=0;
28         memset(vis,0,sizeof(vis));
29         for( int i=0; i<n; i++ ){
30             cin>>title[i];
31         }
32         for( int i=0; i<n; i++ ){
33             for(int j=0; j<m; j++ ){
34                 if(title[i][j]==‘@‘&&!vis[i][j]){
35                     dfs(i,j);
36                     break;
37                 }
38             }
39         }
40         printf("%d\n",ans);
41     }
42 
43     return 0;
44 }