diff --git a/Maths/DigitalRoot.js b/Maths/DigitalRoot.js new file mode 100644 index 0000000000..2e6703e76d --- /dev/null +++ b/Maths/DigitalRoot.js @@ -0,0 +1,34 @@ +const digitalRoot = (num) => { + /** + * Calculates the digital root of a number in constant time. + * @param {number} num - The number to compute the digital root for. + * @returns {number} The digital root of the given number. + * + * @example digitalRoot(456) // returns 6 + * @example digitalRoot(-999) // returns 9 + * @example digitalRoot(0) // returns 0 + */ + if (num < 0) num = -num; + return num === 0 ? num : 1 + ((num - 1) % 9); +}; +/*------------------------------------------------------------------------------------*/ + +const digitalRootRecursive = (num) => { + /** + * Calculates the digital root of a number using recursion. + * @param {number} num - The number to compute the digital root for. + * @returns {number} The digital root of the given number. + * + * @example digitalRootRecursive(456) // returns 6 + * @example digitalRootrecursive(999) // returns 9 + * @example digitalRootRecursive(0) // returns 0 + */ + if (num < 0) num = -num; // Handle negative input by converting to positive + if (num < 10) return num; // Base case for single-digit number + + // Recursive case: sum digits and continue to reduce + const sum = (num % 10) + digitalRootRecursive(Math.floor(num / 10)); + return digitalRootRecursive(sum); // Call digitalRoot recursively to reduce to single digit +}; + +export { digitalRoot, digitalRootRecursive };