feat: add Dudeney number algorithm

Maths/DudeneyNumber.js

@@ -0,0 +1,25 @@
+/**
+ * @function isDudeneyNumber
+ * @description A Dudeney number is a positive integer that is a perfect
+ *   cube such that the sum of its digits equals the cube root of the number.
+ *   For example, 512: cube root of 512 = 8, and 5+1+2 = 8.
+ * @param {number} n - A positive integer
+ * @returns {boolean} - True if n is a Dudeney number, false otherwise
+ * @see https://en.wikipedia.org/wiki/Dudeney_number
+ * @example isDudeneyNumber(512) => true
+ * @example isDudeneyNumber(1) => true
+ * @example isDudeneyNumber(100) => false
+ */
+const isDudeneyNumber = (n) => {
+  if (!Number.isInteger(n) || n < 1) {
+    throw new TypeError('Input must be a positive integer')
+  }
+  const cubeRoot = Math.round(Math.cbrt(n))
+  if (cubeRoot ** 3 !== n) return false
+  const digitSum = String(n)
+    .split('')
+    .reduce((sum, d) => sum + Number(d), 0)
+  return digitSum === cubeRoot
+}
+
+export { isDudeneyNumber }

Maths/test/DudeneyNumber.test.js

@@ -0,0 +1,47 @@
+import { isDudeneyNumber } from '../DudeneyNumber.js'
+
+describe('isDudeneyNumber', () => {
+  test('1 is a Dudeney number (1³=1, 1=1)', () => {
+    expect(isDudeneyNumber(1)).toBe(true)
+  })
+
+  test('512 is a Dudeney number (8³=512, 5+1+2=8)', () => {
+    expect(isDudeneyNumber(512)).toBe(true)
+  })
+
+  test('4913 is a Dudeney number (17³=4913, 4+9+1+3=17)', () => {
+    expect(isDudeneyNumber(4913)).toBe(true)
+  })
+
+  test('5832 is a Dudeney number (18³=5832, 5+8+3+2=18)', () => {
+    expect(isDudeneyNumber(5832)).toBe(true)
+  })
+
+  test('17576 is a Dudeney number (26³=17576, 1+7+5+7+6=26)', () => {
+    expect(isDudeneyNumber(17576)).toBe(true)
+  })
+
+  test('100 is NOT a Dudeney number', () => {
+    expect(isDudeneyNumber(100)).toBe(false)
+  })
+
+  test('8 is NOT a Dudeney number (2³=8, 8≠2)', () => {
+    expect(isDudeneyNumber(8)).toBe(false)
+  })
+
+  test('27 is NOT a Dudeney number (3³=27, 2+7=9≠3)', () => {
+    expect(isDudeneyNumber(27)).toBe(false)
+  })
+
+  test('throws TypeError for zero', () => {
+    expect(() => isDudeneyNumber(0)).toThrow(TypeError)
+  })
+
+  test('throws TypeError for negative input', () => {
+    expect(() => isDudeneyNumber(-512)).toThrow(TypeError)
+  })
+
+  test('throws TypeError for float input', () => {
+    expect(() => isDudeneyNumber(51.2)).toThrow(TypeError)
+  })
+})