printEncoding.java

import java.io.*;
import java.util.*;

public class Main {

    public static void main(String[] args) throws Exception {
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        String str = br.readLine();
        printEncodings(str, "");
    }

    public static void printEncodings(String ques, String ans) {
        if (ques.length() == 0) {
            System.out.println(ans);
            return;
        } else if (ques.length() == 1) {
            if (ques.charAt(0) == '0') {
                return;
            } else {
                String ch0 = ques.substring(0, 1);
                String roq0 = ques.substring(1);
                String code0 = (char)('a' + (Integer.parseInt(ch0) - 1)) + "";
                printEncodings(roq0, ans + code0);
            }
        } else {
            if (ques.charAt(0) == '0') {
                return;
            } else {
                String ch0 = ques.substring(0, 1);
                String roq0 = ques.substring(1);
                String code0 = (char)('a' + (Integer.parseInt(ch0) - 1)) + "";
                printEncodings(roq0, ans + code0);

                String ch01 = ques.substring(0, 2);
                String roq01 = ques.substring(2);
                String code01 = (char)('a' + (Integer.parseInt(ch01) - 1)) + "";

                if (Integer.parseInt(ch01) <= 26) {
                    printEncodings(roq01, ans + code01);
                }
            }
        }
    }
}