Generating numbers

Hello is there some algorithm which can generate random numbers in int[,](two dimentional array).
Let's say I have these numbers :
http://store.picbg.net/pubpic/BA/1E/...a9bbf9ba1e.png
lets say that the blue circle is the current position in the array where the loop have to enter a number,but first I have to check all four directions(current =>down,up,left,right) and if the random number don't exist in these four directions then to enter it in.
My problem is that I don't know how to check all the drections without throwing a error and I don't want to use try & catch.

Thx in advance.

So what happens if you are at 3 instead of 5? How would that look? Or would you only evaluate 6 and 8, instead of the 4 on the other far end? Otherwise this is pretty simple. The number above it, is just the index of the number on the bottom + 1, and then you'd just take the element[current_index - 1] and element[current_index + 1] to get the sides. Otherwise, if the element index is 0 or the upperbound index, check as to whether to return the last index or the first index for the opposite end if that's the way you're going...

You don't need a 2D array to do this. Unless that top row of numbers, is not always going to be sequential and starting from 1, counting by 1, all the time. But even then, I don't see the requirement for a 2D array.

Well the contest want to do it this way , I mean using 2D array.
But what worries now me is that the 2d array will be 1000x1000 which is a lot :D
And I am not sure that there is a way to write such thing and make the code to complete the action for 3 seconds

A 2D array wouldn't be 1000x1000 unless you have some awkward structure, it would be 1000+1000, if your concept is for the 2D array a structure like this:

Code:

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{{1,2,3,4,5},{4,7,8,3,5}}

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I don't even see the point in that...