#1134 - Armstrong Number

Easy • View on LeetCode • View on GitHub

Problem Description

Given an integer n, return true if and only if it is an Armstrong number.

The k-digit number n is an Armstrong number if and only if the kth power of each digit sums to n.

Solution

/**
 * @param {number} n
 * @return {boolean}
 */
var isArmstrong = function(n) {
  const digits = n.toString();
  const digitCount = digits.length;
  const digitSum = digits
    .split('')
    .reduce((sum, digit) => sum + Math.pow(parseInt(digit, 10), digitCount), 0);

  return digitSum === n;
};