Algorithm to get all possible string combinations from array up to certain length

Question

What is the best algorithm to get all possible string combinations from a given array with a minimum & maximum length value.

Note: This adds complexity since the

Answer 1

One thing that is for sure is that what ever the algo use for this , the best time complexity for generation of all the numbers is around O((n^m+1)/(n-1)) (Assuming that you are not using any paralleled programming . ) . (Where n is size of array , m is max length .)

For which any of the above stated algo suits better .