CF1182B.Plus from Picture

普及/提高-

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题目描述

You have a given picture with size w×hw \times h . Determine if the given picture has a single "+" shape or not. A "+" shape is described below:

  • A "+" shape has one center nonempty cell.
  • There should be some (at least one) consecutive non-empty cells in each direction (left, right, up, down) from the center. In other words, there should be a ray in each direction.
  • All other cells are empty.

Find out if the given picture has single "+" shape.

输入格式

The first line contains two integers hh and ww ( 1h1 \le h , w500w \le 500 ) — the height and width of the picture.

The ii -th of the next hh lines contains string sis_{i} of length ww consisting "." and "*" where "." denotes the empty space and "*" denotes the non-empty space.

输出格式

If the given picture satisfies all conditions, print "YES". Otherwise, print "NO".

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

输入输出样例

  • 输入#1

    5 6
    ......
    ..*...
    .****.
    ..*...
    ..*...
    

    输出#1

    YES
    
  • 输入#2

    3 5
    ..*..
    ****.
    .*...
    

    输出#2

    NO
    
  • 输入#3

    7 7
    .......
    ...*...
    ..****.
    ...*...
    ...*...
    .......
    .*.....
    

    输出#3

    NO
    
  • 输入#4

    5 6
    ..**..
    ..**..
    ******
    ..**..
    ..**..
    

    输出#4

    NO
    
  • 输入#5

    3 7
    .*...*.
    ***.***
    .*...*.
    

    输出#5

    NO
    
  • 输入#6

    5 10
    ..........
    ..*.......
    .*.******.
    ..*.......
    ..........
    

    输出#6

    NO
    

说明/提示

In the first example, the given picture contains one "+".

In the second example, two vertical branches are located in a different column.

In the third example, there is a dot outside of the shape.

In the fourth example, the width of the two vertical branches is 22 .

In the fifth example, there are two shapes.

In the sixth example, there is an empty space inside of the shape.

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