305889: CF1106A. Lunar New Year and Cross Counting
Memory Limit：256 MB
Time Limit：2 S
Judge Style：Text Compare
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Description
Lunar New Year and Cross Counting
题意翻译
## 题目描述 在一个 $n \times n$ 的地图中寻找有几个图案，满足 $M(i,j)=M(i-1,j-1)=M(i-1,j+1)=M(i+1,j-1)=M(i+1,j+1)=X$ 形似下图。 ``` X.X .X. X.X ``` 如果图案中心所在位置不同即视作不同。 ## 输入输出格式 ### 输入格式： 第一行正整数 $n (1 \le n \le 500)$，表示地图的大小。 接下来 $n$ 行每行 $n$ 个字符，只包含 **'X' 或 '.'**。 ### 输出格式： 一行一个整数 $k$ 表示图案个数。题目描述
Lunar New Year is approaching, and you bought a matrix with lots of "crosses". This matrix $ M $ of size $ n \times n $ contains only 'X' and '.' (without quotes). The element in the $ i $ -th row and the $ j $ -th column $ (i, j) $ is defined as $ M(i, j) $ , where $ 1 \leq i, j \leq n $ . We define a cross appearing in the $ i $ -th row and the $ j $ -th column ( $ 1 < i, j < n $ ) if and only if $ M(i, j) = M(i - 1, j - 1) = M(i - 1, j + 1) = M(i + 1, j - 1) = M(i + 1, j + 1) = $ 'X'. The following figure illustrates a cross appearing at position $ (2, 2) $ in a $ 3 \times 3 $ matrix. ``` <br></br>X.X<br></br>.X.<br></br>X.X<br></br> ``` Your task is to find out the number of crosses in the given matrix $ M $ . Two crosses are different if and only if they appear in different rows or columns.输入输出格式
输入格式
The first line contains only one positive integer $ n $ ( $ 1 \leq n \leq 500 $ ), denoting the size of the matrix $ M $ . The following $ n $ lines illustrate the matrix $ M $ . Each line contains exactly $ n $ characters, each of them is 'X' or '.'. The $ j $ -th element in the $ i $ -th line represents $ M(i, j) $ , where $ 1 \leq i, j \leq n $ .
输出格式
Output a single line containing only one integer number $ k $ — the number of crosses in the given matrix $ M $ .
输入输出样例
输入样例 #1
5
.....
.XXX.
.XXX.
.XXX.
.....
输出样例 #1
1
输入样例 #2
2
XX
XX
输出样例 #2
0
输入样例 #3
6
......
X.X.X.
.X.X.X
X.X.X.
.X.X.X
......
输出样例 #3
4