diff --git a/Ciphers/AffineCipher.js b/Ciphers/AffineCipher.js index 367cb18597..7aa590c4fe 100644 --- a/Ciphers/AffineCipher.js +++ b/Ciphers/AffineCipher.js @@ -1,8 +1,9 @@ /** - * @description - The affine cipher is a type of monoalphabetic substitution cipher, where each letter in an alphabet is mapped to its numeric equivalent, encrypted using a simple mathematical function, and converted back to a letter + * @description - The affine cipher is a type of monoalphabetic substitution cipher, where each letter in an alphabet is mapped to its numeric equivalent, encrypted using a simple mathematical function, and converted back to a letter * @see - [wiki](https://en.wikipedia.org/wiki/Affine_cipher) */ +import { CoPrimeCheck } from '../Maths/CoPrimeCheck' // Default key for Affine Cipher const key = 'ABCDEFGHIJKLMNOPQRSTUVWXYZ' @@ -44,8 +45,13 @@ function isCorrectFormat (str, a, b) { throw new TypeError('Argument str should be String') } + if (!CoPrimeCheck(a, 26)) { + throw new Error(a + ' is not coprime of 26') + } + return true } + /** * Find character index based on ASCII order * @param {String} char - Character index to be found @@ -62,17 +68,19 @@ function findCharIndex (char) { * @param {Number} b - B coefficient * @return {String} result - Encrypted string */ + function encrypt (str, a, b) { let result = '' if (isCorrectFormat(str, a, b)) { for (let x = 0; x < str.length; x++) { const charIndex = findCharIndex(str[x]) if (charIndex < 0) result += '-1' + ' ' - else result += mod(a * charIndex + b, 26) + ' ' + else result += key.charAt(mod(a * charIndex + b, 26)) + ' ' } } return result.trim() } + /** * Decrypt a Affine Cipher * @param {String} str - String to be decrypted @@ -86,10 +94,12 @@ function decrypt (str, a, b) { str = str.split(' ') for (let x = 0; x < str.length; x++) { if (str[x] === '-1') result += ' ' - else result += key[mod(inverseMod(a, 26) * (parseInt(str[x]) - b), 26)] + else { + const charIndex = findCharIndex(str[x]) + result += key[mod(inverseMod(a, 26) * (charIndex - b), 26)] + } } + return result } - return result } - export { encrypt, decrypt } diff --git a/Ciphers/test/AffineCipher.test.js b/Ciphers/test/AffineCipher.test.js index 632704bce2..51d9cb700d 100644 --- a/Ciphers/test/AffineCipher.test.js +++ b/Ciphers/test/AffineCipher.test.js @@ -6,6 +6,8 @@ describe('Test Affine Cipher', () => { expect(() => encrypt('null', null, null)).toThrow() expect(() => encrypt('null', 1, null)).toThrow() expect(() => encrypt('null', null, 1)).toThrow() + expect(() => encrypt('null', 2, 1)).toThrow() + expect(() => encrypt('null', 4, 1)).toThrow() }) it('Test - 2, Pass invalid input to decrypt function', () => { @@ -13,14 +15,14 @@ describe('Test Affine Cipher', () => { expect(() => decrypt('null', null, null)).toThrow() expect(() => decrypt('null', 1, null)).toThrow() expect(() => decrypt('null', null, 1)).toThrow() + expect(() => encrypt('null', 2, 1)).toThrow() + expect(() => encrypt('null', 4, 1)).toThrow() }) it('Test - 3 Pass string value to encrypt and ecrypt function', () => { - const a = 5 - const b = 8 - expect(decrypt(encrypt('HELLO WORLD', a, b), a, b)).toBe('HELLO WORLD') - expect(decrypt(encrypt('ABC DEF', a, b), a, b)).toBe('ABC DEF') - expect(decrypt(encrypt('Brown fox jump over the fence', a, b), a, b)).toBe( + expect(decrypt(encrypt('HELLO WORLD', 5, 8), 5, 8)).toBe('HELLO WORLD') + expect(decrypt(encrypt('ABC DEF', 3, 5), 3, 5)).toBe('ABC DEF') + expect(decrypt(encrypt('Brown fox jump over the fence', 7, 3), 7, 3)).toBe( 'BROWN FOX JUMP OVER THE FENCE' ) }) diff --git a/Maths/JugglerSequence.js b/Maths/JugglerSequence.js new file mode 100644 index 0000000000..96a2a35150 --- /dev/null +++ b/Maths/JugglerSequence.js @@ -0,0 +1,24 @@ +/* + * Juggler Sequence: https://en.wikipedia.org/wiki/Juggler_sequence + * function jugglerSequence + * Juggler Sequence is a series of integer number in which the first term starts with a positive integer number n + * and the remaining terms are generated from the immediate previous term using the recurrence relation + * Produce Juggler Sequence using number n as the first term of the sequence and store in an array + * Reference: https://www.geeksforgeeks.org/juggler-sequence/ + * jugglerSequence(3) // returns [3, 5, 11, 36, 6, 2, 1 ] + * jugglerSequence(9) // returns [9, 27, 140, 11, 36, 6, 2, 1] + * jugglerSequence(15) // returns [15, 58, 7, 18, 4, 2, 1] + */ + +function jugglerSequence (n) { + const sequence = [] + sequence.push(n) + // Calculate terms until last term is not 1 + while (n !== 1) { + n = Math.floor(n ** ((n % 2) + 0.5)) + sequence.push(n) + } + return sequence +} + +export { jugglerSequence } diff --git a/Maths/test/JugglerSequence.test.js b/Maths/test/JugglerSequence.test.js new file mode 100644 index 0000000000..392047a95b --- /dev/null +++ b/Maths/test/JugglerSequence.test.js @@ -0,0 +1,21 @@ +import { jugglerSequence } from '../JugglerSequence' + +describe('Testing jugglerSequence function', () => { + it('should return [3, 5, 11, 36, 6, 2, 1 ] if the number is 3', () => { + expect(jugglerSequence(3)).toEqual( + expect.arrayContaining([3, 5, 11, 36, 6, 2, 1]) + ) + }) + + it('should return [9, 27, 140, 11, 36, 6, 2, 1] if the number is 9', () => { + expect(jugglerSequence(9)).toEqual( + expect.arrayContaining([9, 27, 140, 11, 36, 6, 2, 1]) + ) + }) + + it('should return [15, 58, 7, 18, 4, 2, 1] if the number is 15', () => { + expect(jugglerSequence(15)).toEqual( + expect.arrayContaining([15, 58, 7, 18, 4, 2, 1]) + ) + }) +})