Plus from Picture
시간 제한1초메모리 제한1024 MB
점과 별로 이루어진 h x w 격자가 주어질 때, 별들이 하나의 중심과 네 방향 팔을 가진 정확히 하나의 더하기 모양을 이루는지 판별한다.
문제
You have a given picture with size . 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.
입력
The first line contains two integers and (, ) --- the height and width of the picture.
The -th of the next lines contains string of length consisting "." and "*" where "." denotes the empty space and "*" denotes the non-empty space.
출력
If the given picture satisfies all conditions, print "YES". Otherwise, print "NO".
힌트
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 .
In the fifth example, there are two shapes.
In the sixth example, there is an empty space inside of the shape.