Algorithm to generate all combinations of a string

Question

I found a link online that shows an algorithm to generate all combinations of a string: http://www.mytechinterviews.com/combinations-of-a-string

Algorithm is copied belo

Answer 1

outstr.deleteCharAt(outstr.length() - 1); 

means that you have

n^(n-1)/2 pairs of combinations.

The iterative for-loop doesn't stop after the recursive function call so you need to delete the last char in the output buffer because you don't want to get

n^n/2 pairs of combinations.

In a graph theory it would be a short circuit.