A9295. Fox and Cross
编程题
普及/提高-
知识点
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.
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.
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.
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 '\#'.
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 #1
5 .#... ####. .#### ...#. .....
输出 #1
YES
输入 #2
4 #### #### #### ####
输出 #2
NO
输入 #3
6 .#.... ####.. .####. .#.##. ###### .#..#.
输出 #3
YES
输入 #4
6 .#..#. ###### .####. .####. ###### .#..#.
输出 #4
NO
输入 #5
3 ... ... ...
输出 #5
YES
说明/提示
In example 1, you can draw two crosses. The picture below shows what they look like.
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.
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.