MAKEMAZE  VALIDATE THE MAZE
MAZE MAKING
There are many algorithms to generate maze. (http://en.wikipedia.org/wiki/Maze_generation_algorithm). After generating the maze we’ve to validate whether it’s a valid maze or not. A valid maze has exactly one entry point and exactly one exit point (exactly 2 openings in the edges) and there must be atleast one path from the entry point to exit point.
Given a maze, just find whether the maze is "valid" or "invalid".
Input Specification:
The first line consists of an integer t, the number of test cases. Then for each test case, the first line consists of two integers m and n, the number of rows and columns in the maze. Then contains the description of the matrix M of order mxn. M[i][j]=# represents a wall and M[i][j]='.' represents a space.
Output Specification:
For each test case find whether the maze is "valid" or "invalid".
Input Constraints:
1<=t<=10000
1<=m<=20
1<=n<=20
Sample Input:
6 4 4 #### #... #.## #.## 5 5 #.### #..## ##..# #.#.# ###.# 1 1 . 5 1 # # . . # 2 2 #. .# 3 4 #..# #.## #.##
Sample Output:
valid valid invalid valid invalid invalid
hide comments
vishal chaudhary:
20131212 23:21:48
i m getting SIGSEGV error , my code id is 7485646 ...plz help..:( 

Swapnil R.Mehta:
20131212 23:21:48
Got AC! Last edit: 20120816 10:19:45 

cegprakash:
20131212 23:21:48
@Prabhat:


winner:
20131212 23:21:48


♘Prabhat:
20131212 23:21:48
what is answer of this


Aditya Pande:
20131212 23:21:48
Last edit: 20121218 15:53:47 

Zhouxing Shi:
20131212 23:21:48
I got WA all the time,could you @pandian @cegprakash tell me why ? THANKS.


Ehor Nechiporenko:
20131212 23:21:48
Could you please answer 2 questions?


Abhishek Mishra:
20131212 23:21:48
very nyc question Last edit: 20120620 18:33:56 

Pandian:
20131212 23:21:48
@Nnavneetsinha : You can't move from one '.' to another '.' with the possible moves up,down,left and right.

Added by:  cegprakash 
Date:  20120511 
Time limit:  1s 
Source limit:  50000B 
Memory limit:  1536MB 
Cluster:  Cube (Intel G860) 
Languages:  All except: ASM64 GOSU 