- Time limit: 10.00 s
- Memory limit: 512 MB
You need to transport a stick through a 2-dimensional maze. The length of the stick is 5 meters and the width is 1 centimeter. The maze consists of blocks of size 1×1 meters. You cannot bend the stick, break it, or lift it. You can only slide it along the floor of the maze.
Input
The first input line contains an integer t: the number of test cases. Then there are t test cases, described as follows:
First there is a line with two numbers, n and m, which indicates the size of the maze: n blocks tall and m blocks wide.
Then there is a line with two numbers, a and b, indicating the position of the entrance and exit, with 2 \le a \le m-1, and 2 \le b \le m-1. The entrance is in the top row, in column a, and the exit is in the bottom row, in column b.
Finally, there are n lines, with m characters on each row. The characters are either 0 or 1, indicating a block of empty space or a block of solid wall, respectively.
All blocks on the perimeter of the maze are walls, with the exception of the entrance and exit, which are empty.
Output
Output t lines, one per test case. For each test case, output YES if there is a way to navigate the stick through the maze from the entrance to the exit, and NO otherwise.
Limits
- 1 \le t \le 50
- 3 \le n \le 30
- 1 \le m \le 30
Example
Here we have four test cases, the first one is illustrated above.
Input:
4 13 16 8 13 1111111011111111 1111111011110001 1111111011110001 1111111011110001 1111111011110001 1000000000000001 1000111011110111 1000111011110111 1000111011110111 1000000011110111 1000000011110111 1000000011110111 1111111111110111 13 16 8 13 1111111011111111 1111111011110001 1111111011110001 1111111011110001 1111111011110001 1000000000000001 1011111011110111 1011111011110111 1011111011110111 1011111011110111 1011111011110111 1000000011110111 1111111111110111 13 16 8 13 1111111011111111 1111111011111111 1111111011110001 1111111011110001 1111111011110001 1000000000000001 1000111011110111 1000111011110111 1000111011110111 1000000011110111 1000000011110111 1000000011110111 1111111111110111 1 3 2 2 101
Output:
YES NO NO YES