Print Encodings

 1. You are given a string str of digits. (will never start with a 0)

2. You are required to encode the str as per following rules

    1 -> a

    2 -> b

    3 -> c

    ..

    25 -> y

    26 -> z

3. Complete the body of printEncodings function - without changing signature - to calculate and print all encodings of str.

Use the input-output below to get more understanding on what is required

123 -> abc, aw, lc

993 -> iic

013 -> Invalid input. A string starting with 0 will not be passed.

103 -> jc

303 -> No output possible. But such a string maybe passed. In this case print nothing.

Input Format

A string str

Output Format

Permutations of str in order hinted by Sample output

Constraints

0 <= str.length <= 10

Sample Input

655196

Sample Output

feeaif

feesf

Solution:

import java.io.*;

import java.util.*;

public class Main {

    public static void main(String[] args) throws Exception {

        Scanner sc = new Scanner(System.in);

        String str = sc.nextLine();

        printEncodings(str,"");

    }

    public static void printEncodings(String str, String ans) {

        if(str.length() == 0){

            System.out.println(ans);

            return;

        }

        

        int ch = (int) (str.charAt(0)-'0');

        

        if(ch >= 1 && ch <= 9){

            str = str.substring(1);

            // single digit

            char alpa = (char)('a' + ch - 1);

            printEncodings(str, ans + alpa);

            // double digit

            if(str.length() != 0)

            if(ch == 1 || ch == 2){

                int c = (int) (str.charAt(0)-'0');

                ch = (ch*10) + c;

                if(ch >= 10 && ch <= 26){

                    str = str.substring(1);

                    alpa = (char)('a' + ch - 1);

                    printEncodings(str,ans+alpa);

                }

            }

        }

        

        

    }

}