UVa 352

 1 #include <cstdio>
 2 #include <cstring>
 3 #define MAXN 30
 4 
 5 int n;
 6 int G[MAXN][MAXN];
 7 bool vis[MAXN][MAXN];
 8 
 9 void dfs(int i, int j)
10 {
11     if (i < 0 || i >= n || j < 0 || j >= n || vis[i][j] || !G[i][j])  return;
12     vis[i][j] = 1;
13     dfs(i-1, j-1);  dfs(i-1, j);  dfs(i-1, j+1);
14     dfs(i, j-1);                  dfs(i, j+1);
15     dfs(i+1, j-1);  dfs(i+1, j);  dfs(i+1, j+1);
16 }
17 
18 int main()
19 {
20 #ifdef LOCAL
21     freopen("in", "r", stdin);
22 #endif
23     int kase = 0;
24     char str[50];
25     while (scanf("%d", &n) != EOF)
26     {
27         for (int i = 0; i < n; i++)
28         {
29             scanf("%s", str);
30             for (int j = 0; j < n; j++)
31                 G[i][j] = str[j] - '0';
32         }
33         memset(vis, 0, sizeof(vis));
34         int cnt = 0;
35         for (int i = 0; i < n; i++)
36             for (int j = 0; j < n; j++)
37             {
38                 if (!vis[i][j] && G[i][j]) 
39                 {
40                     dfs(i, j);
41                     cnt++;
42                 }
43             }
44         printf("Image number %d contains %d war eagles.
", ++kase, cnt); 
45     }
46     return 0;
47 }