CF1059B.Forgery

普及/提高-

通过率：0%

AC君温馨提醒

该题目为【codeforces】题库的题目，您提交的代码将被提交至codeforces进行远程评测，并由ACGO抓取测评结果后进行展示。由于远程测评的测评机由其他平台提供，我们无法保证该服务的稳定性，若提交后无反应，请等待一段时间后再进行重试。

题目描述

Student Andrey has been skipping physical education lessons for the whole term, and now he must somehow get a passing grade on this subject. Obviously, it is impossible to do this by legal means, but Andrey doesn't give up. Having obtained an empty certificate from a local hospital, he is going to use his knowledge of local doctor's handwriting to make a counterfeit certificate of illness. However, after writing most of the certificate, Andrey suddenly discovered that doctor's signature is impossible to forge. Or is it?

For simplicity, the signature is represented as an $n\times m$ grid, where every cell is either filled with ink or empty. Andrey's pen can fill a $3\times3$ square without its central cell if it is completely contained inside the grid, as shown below.

 xxx x.x xxx Determine whether is it possible to forge the signature on an empty $n\times m$ grid.

输入格式

The first line of input contains two integers $n$ and $m$ ( $3 \le n, m \le 1000$ ).

Then $n$ lines follow, each contains $m$ characters. Each of the characters is either '.', representing an empty cell, or '#', representing an ink filled cell.

输出格式

If Andrey can forge the signature, output "YES". Otherwise output "NO".

You can print each letter in any case (upper or lower).

输入输出样例

输入#1
```
3 3
###
#.#
###
```
输出#1
```
YES
```
输入#2
```
3 3
###
###
###
```
输出#2
```
NO
```
输入#3
```
4 3
###
###
###
###
```
输出#3
```
YES
```

输入#4

5 7
.......
.#####.
.#.#.#.
.#####.
.......

输出#4

YES

说明/提示

In the first sample Andrey can paint the border of the square with the center in $(2, 2)$ .

In the second sample the signature is impossible to forge.

In the third sample Andrey can paint the borders of the squares with the centers in $(2, 2)$ and $(3, 2)$ :

we have a clear paper:  ... ... ... ... 
use the pen with center at $(2, 2)$ .  ### #.# ### ... 
use the pen with center at $(3, 2)$ .  ### ### ### ###

In the fourth sample Andrey can paint the borders of the squares with the centers in $(3, 3)$ and $(3, 5)$ .

首页