Hackerrank - CaesarCipher

 Julius Caesar protected his confidential information by encrypting it using a cipher. Caesar's cipher shifts each letter by a number of letters. If the shift takes you past the end of the alphabet, just rotate back to the front of the alphabet. In the case of a rotation by 3, w, x, y and z would map to z, a, b and c.

Original alphabet:      abcdefghijklmnopqrstuvwxyz
Alphabet rotated +3:    defghijklmnopqrstuvwxyzabc

Example

The alphabet is rotated by , matching the mapping above. The encrypted string is .

Note: The cipher only encrypts letters; symbols, such as -, remain unencrypted.

Function Description

Complete the caesarCipher function in the editor below.

caesarCipher has the following parameter(s):

  • string s: cleartext
  • int k: the alphabet rotation factor

Returns

  • string: the encrypted string

Input Format

The first line contains the integer, , the length of the unencrypted string.
The second line contains the unencrypted string, .
The third line contains , the number of letters to rotate the alphabet by.

Constraints



 is a valid ASCII string without any spaces.

Sample Input

11
middle-Outz
2

Sample Output

okffng-Qwvb

Explanation

Original alphabet:      abcdefghijklmnopqrstuvwxyz
Alphabet rotated +2:    cdefghijklmnopqrstuvwxyzab

m -> o
i -> k
d -> f
d -> f
l -> n
e -> g
-    -
O -> Q
u -> w
t -> v
z -> b
import java.io.*;
import java.math.*;
import java.security.*;
import java.text.*;
import java.util.*;
import java.util.concurrent.*;
import java.util.function.*;
import java.util.regex.*;
import java.util.stream.*;
import static java.util.stream.Collectors.joining;
import static java.util.stream.Collectors.toList;

class Result {

  public static String caesarCipher(String s, int k) {
        String res = "";
        k = k%26;

        for (int i = 0; i < s.length(); i++) {
            if (Character.isUpperCase(s.charAt(i))) {
                int temp = (int) s.charAt(i);
                System.out.println(s.charAt(i) +" "+temp);
                temp += k;
                temp = temp <= 90 ? temp : 64 + (temp % 90);
                res += (char) temp;

            } else if (Character.isLowerCase(s.charAt(i))) {
                int temp = (int) s.charAt(i);
                System.out.println(s.charAt(i) +" "+temp);
                temp += k;
                temp = temp <= 122 ? temp : 96 + (temp % 122);
                res += (char) temp;
            } else {
                res += s.charAt(i);
            }

        }

        return res;
    }



}

public class Solution {
    public static void main(String[] args) throws IOException {
        BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(System.in));
        BufferedWriter bufferedWriter = new BufferedWriter(new FileWriter(System.getenv("OUTPUT_PATH")));

        int n = Integer.parseInt(bufferedReader.readLine().trim());

        String s = bufferedReader.readLine();

        int k = Integer.parseInt(bufferedReader.readLine().trim());

        String result = Result.caesarCipher(s, k);

        bufferedWriter.write(result);
        bufferedWriter.newLine();

        bufferedReader.close();
        bufferedWriter.close();
    }
}


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