Efficiently generating unique pairs of integers

Question

In MATLAB, I would like to generate n pairs of random integers in the range [1, m], where each pair is unique. For uniqueness, I consider the order

Answer 1

This is more of a general approach rather then a matlab solution.

How about you do the following first you fill a vector like the following.

x[n] = rand()
x[n + 1] = x[n] + rand() %% where rand can be equal to 0.

Then you do the following again

x[n][y] = x[n][y] + rand() + 1

And if

x[n] == x[n+1]

You would make sure that the same pair is not already selected.

After you are done you can run a permutation algorithm on the matrix if you want them to be randomly spaced.

This approach will give you all the possibility or 2 integer pairs, and it runs in O(n) where n is the height of the matrix.