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

Simplest way of calculating the possible combinations of strings is here ...

Mathematically to find R combinations in a given lot of N = NcR

So what we are finding here is, all possible combinations = Nc0 + Nc1 .... + Ncn = 2 Pow N

So you get 2 Pow N combinations for given word of length N characters.

If you represent 1 to (2 Pow N) integers in binary, and place your char in the place where 1 is present, finally you would get the solution.

Example:

Input : ABC

Solution :

ABC length is 3. So possible combinations 2 Pow 3 = 8

If 0 - 8 represented in binary

000 =

001 = C

010 = B

011 = BC

100 = A

101 = AC

110 = AB

111 = ABC

all possible combinations are shown above.