Answer to Question #53865 in Software Engineering for aa

Question

Given a square maze (A) of dimension N, every entry (Aij) in the maze is either an open cell 'O' or a wall 'X'. A rat can travel to its adjacent locations (left, right, top and bottom), but to reach a cell, it must be open. Given the locations of R rats, can you find out whether all the rats can reach others or not?

Input Format:

Input will consist of three parts, viz.

1. Size of the maze (N)
2. The maze itself (A = N * N)
3. Number of rats (R)
4. Location of R rats (Xi, Yi)

Note:
(Xi,Yi) will represents the location of the i-th rat.
Locations are 1-index based.



Output Format:

Print "Yes" if the rats can reach each other, else print "No"


Constraints:

1<=N<=350

Aij = {'O','X'}

1<=R<=N*N

1<=Xi<=N

1<=Yi<=N