We use cookies to ensure you have the best browsing experience on our website. Please read our cookie policy for more information about how we use cookies.
  1. Prepare
  2. Algorithms
  3. Strings
  4. Caesar Cipher
  5. Discussions

Caesar Cipher

Sort by

recency

|

1285 Discussions

|

  • spriyamalar
     + 0 comments
    static Map<Character, Integer> smallcharintmap = new HashMap<>();
static Map<Integer, Character> smallintcharmap = new HashMap<>();

static Map<Character, Integer> capscharintmap = new HashMap<>();
static Map<Integer, Character> capsintcharmap = new HashMap<>();

static {
    char smallstart = 'a';
    char capstart = 'A';

    for(int i=1;i<=26;i++) {
        smallcharintmap.put(smallstart, i);
        smallintcharmap.put(i, smallstart);
        smallstart++;

        capscharintmap.put(capstart, i);
        capsintcharmap.put(i, capstart);
        capstart++;
    }
}

public static String caesarCipher(String str, int k) {
    StringBuilder resultBuilder = new StringBuilder();
    for(int i = 0; i < str.length(); i++) {
        Character ch = str.charAt(i);
        if(Character.isAlphabetic(ch)) {
            if(Character.isLowerCase(ch)) {
                int key = (smallcharintmap.get(ch) + k)%26;
                resultBuilder.append(smallintcharmap.get(key == 0 ? 26 : key));
            } else if(Character.isUpperCase(ch)) {
                int key = (capscharintmap.get(ch) + k)%26;
                resultBuilder.append(capsintcharmap.get(key == 0? 26 : key));
            }
        } else {
            resultBuilder.append(ch);
        }
    }
    return resultBuilder.toString();
}

  • dhengekarshreya1
     + 0 comments
    int base;
for(int i=0; i<s.size(); i++){
        if(isalpha(s[i])){
                if(islower(s[i])){
                        base = 'a';
                }else{
                        base = 'A';
                }
                s[i] = ((s[i] - base + k) % 26) + base;
        }
}
return s;

    }

  • afzal_saiyed931
     + 0 comments
    def getEncryptedLetter(s, k, isUpper=True):
    startChar = "A" if isUpper else "a"
    endChar = "Z" if isUpper else "z"
    num = ord(s)
    k = k % 26
    if num + k > ord(endChar):
        diff = (num + k) - ord(endChar)
        new_num = ord(startChar) + diff - 1
    else:
        new_num = num + k
    return chr(new_num)
    
    
def caesarCipher(s, k):
    # Write your code here
    excrypted_str = ""
    for i in s:
        if ("A" <= i <= "Z") or ("a" <= i <= "z"):
            excrypted_str += getEncryptedLetter(i, k, "A" <= i <= "Z")
            continue
        excrypted_str += i
    return excrypted_str

  • yashdeora98294
     + 0 comments

    Here is problem solution in python java c++ c and javascript - https://programmingoneonone.com/hackerrank-caesar-cipher-problem-solution.html

  • prnc_soni
     + 0 comments

    simple javascript solution with time and space complexity both O(n):

    var caesarCipher = function (s, k) {
    let strArr = [];
    for (const ch of s) {
        if (!/^[a-zA-Z]$/.test(ch)) {
            strArr.push(ch);
        } else {
            strArr.push(rotatedChar(ch, k));
        }

    }
    return strArr.join('');
}

function rotatedChar(char, k) {
    let smallLetters = "abcdefghijklmnopqrstuvwxyz"
    let capitalLetters = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";
    if (smallLetters.includes(char)) {
        let index = smallLetters.indexOf(char);
        return smallLetters.charAt((index + k) % 26);
    } else {
        let index = capitalLetters.indexOf(char);
        return capitalLetters.charAt((index + k) % 26);
    }
}