Algorithm to print count and possible string outcomes of a given input string

Write an Efficient algorithm to print count and possible string outcomes of a given input string by retaining order and considering all characters during this process
Problem: given a input string as "0000" and following input scheme for the zeroes, print the possible outcomes by retaining order of the characters. input scheme: a "0" b "00" c "000" d "0000" example: "aaaa" is one string outcome and bb is another string outcome