As far my knowledge , I cannot find any greedy pattern here. Greedy solution is to pick the optimal solution at that point. Correct me if I am wrong.

Isn't it that the given grid should be a square grid ? , but there are test cases where the grid is not a square matrice. E.g in test case 1:

3
mpxz
abcd
wlmf
4
abc
hjk
mpq
rtv

Test cases contain mixed end of lines, sometime there is "\r" in the end, sometime there is none. Had to spend hackos to find this. Please fix the test cases (at least case#4).

I solved the problem. I'm getting all right except the test case 10. I checked the results by running on my computer and compared with the actual results. It is right as well, but it is showing wrong answer. can you please let me know why ?

https://www.hackerrank.com/challenges/grid-challenge/submissions/code/3052512

python solution

the thing that outrages me is the initial code is not correct.

you need to add a for loop for t instead of just read it as the code initiated.

#!/bin/python

import sys

def gridChallenge(grid):
    for i in range(n):
        grid[i] = sorted(grid[i])
    for i in range(n-1):
        for j in range(n):
            if grid[i][j]>grid[i+1][j]:
                return "NO"
    return "YES"        
        

if __name__ == "__main__":
    t = int(raw_input().strip())
    for _ in range(t):
        n = int(raw_input().strip())
        grid = []
        grid_i = 0
        for grid_i in xrange(n):
            grid_t = str(raw_input().strip())
            grid.append(grid_t)
        print gridChallenge(grid)