add CheckKishnamurthyNumber

Author: suryapratapsinghsuryavanshi

Maths/CheckKishnamurthyNumber.js

@@ -0,0 +1,40 @@
+/*
+ Problem statement and Explanation : https://www.geeksforgeeks.org/check-if-a-number-is-a-krishnamurthy-number-or-not-2/
+
+ krishnamurthy number is a number the sum of the all fectorial of the all dights is equal to the number itself.
+ 145 => 1! + 4! + 5! = 1 + 24 + 120 = 145
+*/
+
+// factorail utility method.
+const factorial = (n) => {
+ let fact = 1
+ while (n !== 0) {
+ fact = fact * n
+ n--
+ }
+ return fact
+}
+
+/**
+ * krishnamurthy number is a number the sum of the factorial of the all dights is equal to the number itself.
+ * @param {Number} number a number for checking is krishnamurthy number or not.
+ * @returns return correspond boolean vlaue, if the number is krishnamurthy number return `true` else return `false`.
+ * @example 145 => 1! + 4! + 5! = 1 + 24 + 120 = 145
+ */
+const CheckKishnamurthyNumber = (number) => {
+ // firstly, check that input is a number or not.
+ if (typeof number !== 'number') {
+ return new TypeError('Argument is not a number.')
+ }
+ // create a variable to store the sum of all digits factorial.
+ let sumOfAllDigitFactorial = 0
+ // convert the number to string for convenience.
+ String(number).split('').map(digit => {
+ // split one by one digit and calculate factorial and store to the variable.
+ return (sumOfAllDigitFactorial += factorial(Number(digit)))
+ })
+ // if the sumOftheFactorial is equal to the given number it means the number is a Krishnamurthy number.
+ return sumOfAllDigitFactorial === number
+}
+
+module.exports = CheckKishnamurthyNumber