Caesar Cipher Hacker Rank Solution Best & Easiest

Posted by admin October 12, 2022
Caesar Cipher Problem Solution
Caesar Cipher Problem Solution

In this post, we will solve the Caesar Cipher HackerRank Solution. This problem (Caesar Cipher) is a part of the HackerRank Problem Solving series.

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

Tower Breakers Hacker Rank Solution

Problem solution in Python programming:

def caesarCipher(s, k):
    # Write your code here
    ret = []

    for i in range(len(s)):
        if (s[i].islower()):
            ret.append(chr(97 + ((ord(s[i]) + k) - 97) % 26))
        elif (s[i].isupper()):
            ret.append(chr(65 + ((ord(s[i]) + k) - 65) % 26))
        else:
            ret.append(s[i])
    
    return "".join(ret)

Problem solution in JavaScript programming:

function caesarCipher(s, k) {
    var alphabet = 'abcdefghijklmnopqrstuvwxyz'.split("");
    var cipher = {};
    var output = "";
    
    // define cipher
    for(var i = 0; i< alphabet.length; i++) {
        cipher[alphabet[i]] = alphabet[(i+k)%26];
        cipher[alphabet[i].toUpperCase()] = alphabet[(i+k)%26].toUpperCase();
    }
    
    // apply cipher
    for(var i in s.split("")) {
        output += (cipher[s[i]] != undefined ? cipher[s[i]] : s[i]);
    }
    
    return output;
}

Problem solution in C# programming:

public static string caesarCipher(string s, int k)
    {
        string alphabet = "abcdefghijklmnopqrstuvwxyz";
        StringBuilder res = new StringBuilder();
        if (k > alphabet.Length) k %= alphabet.Length;
        for (int i = 0; i < s.Length; i++)
        {
            if (char.IsLetter(s[i]))
            {
                int index = alphabet.IndexOf(char.ToLower(s[i]));
                int resindex = ((index + k) > (alphabet.Length - 1)) ? index + k - alphabet.Length : index + k;
                res.Append(char.IsUpper(s[i]) ? char.ToUpper(alphabet.ElementAt(resindex)) : alphabet.ElementAt(resindex));
            }
            else
            {
                res.Append(s[i]);
            }
        }
        return res.ToString();
    }