Permutations for digits represented by Phone Number

This is a stackoverflow question: http://stackoverflow.com/questions/1851239/permutations-for-digits-represented-by-phone-number

This can be done by dynamic programming and just need to keep track of the previous result list and build result based on it.

public static List<String> allWordsFromPhonePad(int number){

HashMap<Integer, String > h = new HashMap<Integer, String>(){{

        put(1,"");

        put(2, "ABC");

        put(3, "DEF");

        put(4, "GHI");

        put(5, "JKL");

        put(6, "MNO");

        put(7, "PQRS");

        put(8, "TUV");

        put(9, "WXYZ");

        put(0, "");

    }};

    List<String> result = new ArrayList<String>();

    result.add("");

    while(number>0){

    int last = number%10;

    List<String> temp = new ArrayList<String>();

   

    for(String s: result){

    String map = h.get(last);

    for(char c : map.toCharArray()){

    temp.add(String.valueOf(c) + s);

    }

    }    

    number = (number-last)/10;

    if(!temp.isEmpty())

    result = temp;

    }

   

    return result;

}