How to get 2D array possible combinations

Question

I have the following 2D array:

String[M][]

String[0]
   \"1\",\"2\",\"3\"

String[1]
   \"A\", \"B\"
   .
   .
   .
String[M-1]
   \"!\"

A

Answer 1

Should be straight forward to do with recursion.

Let me rephrase a bit, so the terminology is less confusing.

We will call String[] as Token List, which is a list of Tokens

Now you have a List of Token List, you want to get one Token from each Token List available, and find out all combination.

What you need to do is, given a list of TokenList

• If the List is having only one TokenList, the content of the Token List itself is all combinations
• Else, make a sub-list by excluding the first Token List, and find out all combinations of that sub list. When you have the combinations, the answer is simply loop through your first token list, and generate all combinations using each token in the token list, and the result combinations.

I am only giving a psuedo code:

List allCombinations(List listOfTokenList) {
  if (length of strings == 1) {
    return strings[0];
  }


  List subListCombinations 
      = allCombination(listOfTokenList.subList(1));  // sublist from index 1 to the end


  List result;
  for each (token in listOfTokenList[0]) {
    for each (s in subListCombination) {
      result.add(token + s);
    }
  }
  return result;
}