Easiest approch I found on CPP:

string gridChallenge(vector grid) { bool ok = true; int n = grid.size();

for (int i = 0; i < n; i++) {
    sort(grid[i].begin(), grid[i].end());    //Sorting taking care of row's
}

for (int i = 0; i < n; i++) {
    for (int j = 0; j < grid[i].size()-1; j++) {
        if(grid[j][i] > grid[j+1][i]) //Taking care of coloumb
        {
            return "NO";
        }
    }
}

return "YES";

}