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
s = There’s-a-starman-waiting-in-the-sky
k=3
The alphabet is rotated by 3, matching the mapping above. The encrypted string is
Wkhuh’v-d-vwdupdq-zdlwlqj-lq-wkh-vnb.
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
1<=n<=100
0<=k<=100
s 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
TABLE OF CONTENTS
Caesar Cipher HackerRank Solution in C
#include <stdio.h>
#include <string.h>
#include <math.h>
#include <stdlib.h>
int main() {
/* Enter your code here. Read input from STDIN. Print output to STDOUT */
int n,i,j,k;
char ar[101];
unsigned char x;
scanf("%d",&n);
scanf("%s",ar);
scanf("%d",&k);
for(i=0;i<n;i++)
{
x=ar[i];
if(x>=97 && x<=122)
{
x=x+(k%26);
if(x>122)
{
x=96+(x-122);
}
ar[i]=x;
}
else if(x>=65 && x<=90)
{
x=x+(k%26);
if(x>90)
{
x=64+(x-90);
}
ar[i]=x;
}
}
printf("%s",ar);
return 0;
}
Caesar Cipher HackerRank Solution in C++
#include <iostream>
#include <string>
using namespace std;
int main() {
int N = 0, K = 0;
string str, dummy;
cin >> N; getline(cin, dummy);
getline(cin, str);
cin >> K;
int len = str.length();
for (int i = 0; i < len; ++i)
{
if (65 <= str[i] && str[i] <= 90)
str[i] = char(65 + ((str[i] - 65) + K) % 26);
else if (97 <= str[i] && str[i] <= 122)
str[i] = char(97 + ((str[i] - 97) + K) % 26);
}
cout << str << endl;
return 0;
}
Caesar Cipher HackerRank Solution in Java
import java.io.*;
import java.util.*;
import java.text.*;
import java.math.*;
import java.util.regex.*;
public class Solution {
public static void main(String[] args) {
Scanner s = new Scanner(System.in);
int len = s.nextInt(); s.nextLine();
String str = s.nextLine();
int shift = s.nextInt();
char sarr[] = str.toCharArray();
for (int i=0; i<sarr.length; i++) {
sarr[i] = cryptIt(sarr[i], shift);
}
System.out.println(new String(sarr));
}
public static char cryptIt(char c, int shift) {
if (!Character.isAlphabetic(c)) return c;
char base = 'A';
if (c >= 'a') base = 'a';
return (char)(((c - base + shift) % 26) + base);
}
}
Caesar Cipher HackerRank Solution in Python
import sys
INDEX_TABLE = {'a': 0, 'b': 1, 'c': 2, 'd': 3, 'e': 4, 'f': 5, 'g': 6, 'h': 7, 'i': 8, 'j': 9, 'k': 10, 'l': 11, 'm': 12, 'n': 13, 'o': 14, 'p': 15, 'q': 16, 'r': 17, 's': 18, 't': 19, 'u': 20, 'v': 21, 'w': 22, 'x': 23, 'y': 24, 'z': 25}
raw_alphabet = 'abcdefghijklmnopqrstuvwxyz'
sys.stdin.readline()
to_encode = sys.stdin.readline()
shift_amount = int(sys.stdin.readline()) % 26
encoded_alphabet = raw_alphabet[shift_amount:] + raw_alphabet[0:shift_amount]
# print encoded_alphabet
result_str = ''
for ch in to_encode:
is_upper = ch.isupper()
ch = ch.lower()
if ch in INDEX_TABLE:
if is_upper:
result_str += encoded_alphabet[INDEX_TABLE[ch]].upper()
else:
result_str += encoded_alphabet[INDEX_TABLE[ch]]
else:
result_str += ch
print result_str
Caesar Cipher HackerRank Solution in C#
using System;
using System.Collections.Generic;
using System.IO;
class Solution {
static void Main(String[] args) {
/* Enter your code here. Read input from STDIN. Print output to STDOUT. Your class should be named Solution */
var length = int.Parse(Console.ReadLine());
var s = Console.ReadLine();
var k = int.Parse(Console.ReadLine());
foreach (var c in s)
{
if (!((c >= 'a' && c <= 'z') || (c >= 'A' && c <= 'Z')))
{
Console.Write(c);
}
else
{
var isLower = (c >= 'a' && c <= 'z');
var c1 = c.ToString().ToLower()[0];
c1 += (char)(k % 26);
if (c1 > 'z')
{
c1 -= (char)26;
}
if (!isLower)
{
c1 = c1.ToString().ToUpper()[0];
}
Console.Write(c1);
}
}
Console.WriteLine();
}
}
Attempt Caesar Cipher HackerRank Challenge
Link – https://www.hackerrank.com/challenges/caesar-cipher-1/
Next HackerRank Challenge Solution
Link – https://exploringbits.com/mars-exploration-hackerrank-solution/