Hacker Rank Practice solution - Ciphering and Deciphering

Hacker Rank questions and solution:

1. Ciphering and Deciphering(Passed all the test cases)

Ans: Adding only the methods and it's solution for below 4 steps:

        a) To change the given string to uppercase from lowercase and vise-versa.

        b) To reverse the string using StringBuilder

        c) To convert the even place letters with corresponding ascii value

        d) To replace all the space with "*";

        e) Return the ciphered string.

        d) For Deciphering reverse the above step.

        

Solution: 

public class CipherDecipher {


    public String ciphering(String normal){

        //converted String to array
        char[] caseSwap = normal.toCharArray();

        //converted upper to lower and vise-versa
        for(int i = 0 ; i <caseSwap.length; i++){
            if(Character.isDigit(caseSwap[i])){
                return null;
            }
            if(caseSwap[i]>='a' && caseSwap[i] <='z'){
                caseSwap[i]-=32;
            } else if(caseSwap[i]>='A' && caseSwap[i] <='Z'){
                caseSwap[i]+=32;
            }
        }

        //reverse
//        System.out.println(new String(caseSwap));
        normal = new String(caseSwap);
        normal = (new StringBuilder(normal).reverse().toString());

        //replace
        normal = normal.replace(" ", "*");

        //character to ascii value
        char[] asciiValue = normal.toCharArray();
        String finalValue="";
        for(int i = 0; i<asciiValue.length ; i++){
            if(i%2==1) {
//                finalValue += Integer.toString((int) asciiValue[i]);
                finalValue += String.valueOf((int) asciiValue[i]);
                System.out.println("final value of toString "+ finalValue);
            } else {
                finalValue += asciiValue[i];
            }
        }

        //added 3 to the value
        finalValue += "3";
        return finalValue;
    }







    public String deciphering(String ciphered){
        char[] v1 = ciphered.toCharArray();

        //3 removed. can also be solved using substring method of String class.
        String removeThree = "";
        for(int i = 0; i< v1.length-1; i++) {
            removeThree += v1[i];
        }
        char[] asciiValue = removeThree.toCharArray();


        //converting the ascii to letters
        String finalWord ="";
        String temp = "";
        int comparision = 0;
        for(int i = 0; i< asciiValue.length; i++){
            if(Character.isDigit(asciiValue[i])){
                temp = temp+asciiValue[i];
                if((temp.length()>=2 && temp.length()<=3)){
                    comparision  = Integer.parseInt(temp);
                } else continue;

                if((comparision>=32 && comparision <=126)){
                    char correspondingCharValue = (char) comparision;
                    finalWord += correspondingCharValue;
               }

            } else {
                finalWord += asciiValue[i];
                temp = "";
            }
        }


        //replace
        finalWord = finalWord.replace("*", " ");


        //reverse
        finalWord = (new StringBuilder(finalWord).reverse().toString());

        //upper to lower case and vise-versa
        char[] caseSwap = finalWord.toCharArray();
        for(int i = 0 ; i <caseSwap.length; i++){
            if(caseSwap[i]>='a' && caseSwap[i] <='z'){
                caseSwap[i]-=32;
            } else if(caseSwap[i]>='A' && caseSwap[i] <='Z'){
                caseSwap[i]+=32;
            }
        }

        finalWord = new String(caseSwap);

        return finalWord;
    }