UVa 352

　　题目大意：和UVa 572 - Oil Deposits一下，寻找“八连块”的个数。用DFS解决。

#include <cstdio>
#include <cstring>
#define MAXN 30

int n;
int G[MAXN][MAXN];
bool vis[MAXN][MAXN];

void dfs(int i, int j)
{
    if (i < 0 || i >= n || j < 0 || j >= n || vis[i][j] || !G[i][j])  return;
    vis[i][j] = 1;
    dfs(i-1, j-1);  dfs(i-1, j);  dfs(i-1, j+1);
    dfs(i, j-1);                  dfs(i, j+1);
    dfs(i+1, j-1);  dfs(i+1, j);  dfs(i+1, j+1);
}

int main()
{
#ifdef LOCAL
    freopen("in", "r", stdin);
#endif
    int kase = 0;
    char str[50];
    while (scanf("%d", &n) != EOF)
    {
        for (int i = 0; i < n; i++)
        {
            scanf("%s", str);
            for (int j = 0; j < n; j++)
                G[i][j] = str[j] - '0';
        }
        memset(vis, 0, sizeof(vis));
        int cnt = 0;
        for (int i = 0; i < n; i++)
            for (int j = 0; j < n; j++)
            {
                if (!vis[i][j] && G[i][j]) 
                {
                    dfs(i, j);
                    cnt++;
                }
            }
        printf("Image number %d contains %d war eagles.
", ++kase, cnt); 
    }
    return 0;
}