POJ 1979 Red and Black

 1 #include<iostream>
 2 #include<cstring>
 3 using namespace std;
 4 const int N = 30;
 5 int row, col, sx, sy;
 6 int vis[N][N];
 7 char a[N][N];
 8 int dir[4][2] = {{1, 0}, {-1, 0}, {0, -1}, {0, 1}};
 9 void dfs(int x, int y){
10     for(int i = 0; i < 4; i++){
11         int tx = dir[i][0] + x, ty = dir[i][1] + y;
12         if(tx < 0 || tx > row - 1 || ty < 0 || ty > col - 1)    continue;
13         if(!vis[tx][ty] && a[tx][ty] == ‘.‘){
14             vis[tx][ty] = 1;
15             dfs(tx, ty);
16         }
17     }
18 }
19 int main(){
20     while(cin >> col >> row){
21         if(col == 0 && row == 0)    break;
22         int cnt = 0;
23         memset(vis, 0, sizeof(vis));
24         for(int i = 0; i < row; i++){
25             for(int j = 0; j < col; j++){
26                 cin >> a[i][j];
27                 if(a[i][j] == ‘@‘){
28                     sx = i;    sy = j;
29                 }
30             }
31         }
32         vis[sx][sy] = 1;
33         dfs(sx, sy);
34         for(int i = 0; i < row; i++){
35             for(int j = 0; j < col; j++){
36                 if(vis[i][j] == 1)    cnt++;
37             }
38         }
39         cout << cnt << endl;    
40     }
41     return 0;
42 }

 1 #include<iostream>
 2 #include<cstring>
 3 #include<cstdio>
 4 using namespace std;
 5 struct node{
 6     int x, y;
 7 }que[2003];
 8 char a[23][23];
 9 int book[25][25], cnt, h, w;
10 int pos[4][2] = {{1, 0}, {-1, 0}, {0, -1}, {0, 1}};
11 void bfs(int rx, int ry){
12     int head = 1, tail = 1;
13         que[tail].x = rx;    que[tail].y = ry;
14         book[rx][ry] = 1;
15         tail++;    cnt++;
16         while(head < tail){
17             for(int i = 0; i < 4; i++){
18                 int tx = que[head].x + pos[i][0];
19                 int ty = que[head].y + pos[i][1];
20                 if(tx < 0 || tx > h - 1 || ty < 0 || ty > w - 1)    continue;
21                 if(a[tx][ty] == ‘.‘ && book[tx][ty] == 0){
22                     cnt++;    
23                     book[tx][ty] = 1;
24                     que[tail].x = tx;    que[tail].y = ty;
25                     tail++;
26                 }
27             }
28             head++;
29         }
30 }
31 int main(){
32     while(cin >> w >> h){
33         if(w == 0 && h == 0)    break;
34         memset(a, 0, sizeof(a));
35         memset(book, 0, sizeof(book));
36         cnt = 0;
37         for(int i = 0; i < h; i++){
38             cin >> a[i];
39         }
40         int rx, ry;
41         for(int i = 0; i < h; i++){
42             for(int j = 0; j < w; j++){
43                 if(a[i][j] == ‘@‘){
44                     rx = i;
45                     ry = j;
46                 }
47             }
48         }
49         bfs(rx, ry);
50         cout << cnt << endl;
51     }
52     return 0;
53 }