merge: Fix GetEuclidGCD (TheAlgorithms#1068)

* Fix GetEuclidGCD Implement the actual Euclidean Algorithm * Replace == with === * Lua > JS * Standard sucks * Oops * Update GetEuclidGCD.js * Updated Documentation in README.md Co-authored-by: github-actions <${GITHUB_ACTOR}@users.noreply.github.com>

Author: appgurueu

DIRECTORY.md

@@ -18,6 +18,7 @@
 * **Cellular-Automata**
  * [ConwaysGameOfLife](Cellular-Automata/ConwaysGameOfLife.js)
 * **Ciphers**
+ * [AffineCipher](Ciphers/AffineCipher.js)
  * [Atbash](Ciphers/Atbash.js)
  * [CaesarsCipher](Ciphers/CaesarsCipher.js)
  * [KeyFinder](Ciphers/KeyFinder.js)

Maths/GetEuclidGCD.js

@@ -1,32 +1,20 @@
-/*
- Problem statement and Explanation : https://en.wikipedia.org/wiki/Euclidean_algorithm
-
- In this method, we have followed the iterative approach to first
- find a minimum of both numbers and go to the next step.
-*/
-
 /**
- * GetEuclidGCD return the gcd of two numbers using Euclidean algorithm.
- * @param {Number} arg1 first argument for gcd
- * @param {Number} arg2 second argument for gcd
- * @returns return a `gcd` value of both number.
+ * GetEuclidGCD Euclidean algorithm to determine the GCD of two numbers
+ * @param {Number} a integer (may be negative)
+ * @param {Number} b integer (may be negative)
+ * @returns {Number} Greatest Common Divisor gcd(a, b)
  */
-const GetEuclidGCD = (arg1, arg2) => {
- // firstly, check that input is a number or not.
- if (typeof arg1 !== 'number' || typeof arg2 !== 'number') {
- return new TypeError('Argument is not a number.')
+export function GetEuclidGCD (a, b) {
+ if (typeof a !== 'number' || typeof b !== 'number') {
+ throw new TypeError('Arguments must be numbers')
  }
- // check that the input number is not a negative value.
- if (arg1 < 1 || arg2 < 1) {
- return new TypeError('Argument is a negative number.')
+ if (a === 0 && b === 0) return undefined // infinitely many numbers divide 0
+ a = Math.abs(a)
+ b = Math.abs(b)
+ while (b !== 0) {
+ const rem = a % b
+ a = b
+ b = rem
  }
- // Find a minimum of both numbers.
- let less = arg1 > arg2 ? arg2 : arg1
- // Iterate the number and find the gcd of the number using the above explanation.
- for (less; less >= 2; less--) {
- if ((arg1 % less === 0) && (arg2 % less === 0)) return (less)
- }
- return (less)
+ return a
 }
-
-export { GetEuclidGCD }