Fox and Cross
题意翻译
有一个 $n\times n$ 的矩阵,每个点为 `.` 或 `#` ,问该矩阵是否能够分解成多个如下图的由 `#` 组成的十字形:
```
x # x
# # #
x # x
```
`x` 表示任意字母。
题目描述
Fox Ciel has a board with $ n $ rows and $ n $ columns. So, the board consists of $ n×n $ cells. Each cell contains either a symbol '.', or a symbol '\#'.
A cross on the board is a connected set of exactly five cells of the board that looks like a cross. The picture below shows how it looks.
![](https://cdn.luogu.com.cn/upload/vjudge_pic/CF389B/5ccac31668e0d529fa8a5f9e69b4dcfcf1f3b650.png)Ciel wants to draw several (may be zero) crosses on the board. Each cross must cover exactly five cells with symbols '\#', and any cell with symbol '\#' must belong to some cross. No two crosses can share a cell.
Please, tell Ciel if she can draw the crosses in the described way.
输入输出格式
输入格式
The first line contains an integer $ n $ ( $ 3<=n<=100 $ ) — the size of the board.
Each of the next $ n $ lines describes one row of the board. The $ i $ -th line describes the $ i $ -th row of the board and consists of $ n $ characters. Each character is either a symbol '.', or a symbol '\#'.
输出格式
Output a single line with "YES" if Ciel can draw the crosses in the described way. Otherwise output a single line with "NO".
输入输出样例
输入样例 #1
5
.#...
####.
.####
...#.
.....
输出样例 #1
YES
输入样例 #2
4
####
####
####
####
输出样例 #2
NO
输入样例 #3
6
.#....
####..
.####.
.#.##.
######
.#..#.
输出样例 #3
YES
输入样例 #4
6
.#..#.
######
.####.
.####.
######
.#..#.
输出样例 #4
NO
输入样例 #5
3
...
...
...
输出样例 #5
YES
说明
In example 1, you can draw two crosses. The picture below shows what they look like.
![](https://cdn.luogu.com.cn/upload/vjudge_pic/CF389B/2961c8465879f5caacf5ebd47c02d06b75cd444e.png)In example 2, the board contains 16 cells with '\#', but each cross contains 5. Since 16 is not a multiple of 5, so it's impossible to cover all.