I need to calculate permutations iteratively. The method signature looks like:

int[][] permute(int n)

For n = 3 for example, the return value would be:

[[0,1,2],
 [0,2,1],
 [1,0,2],
 [1,2,0],
 [2,0,1],
 [2,1,0]]

How would you go about doing this iteratively in the most efficient way possible? I can do this recursively, but I'm interested in seeing lots of alternate ways to doing it iteratively.