Add solution #3099

Author: JoshCrozier

README.md

@@ -2168,6 +2168,7 @@
 3091|[Apply Operations to Make Sum of Array Greater Than or Equal to k](./solutions/3091-apply-operations-to-make-sum-of-array-greater-than-or-equal-to-k.js)|Medium|
 3095|[Shortest Subarray With OR at Least K I](./solutions/3095-shortest-subarray-with-or-at-least-k-i.js)|Easy|
 3097|[Shortest Subarray With OR at Least K II](./solutions/3097-shortest-subarray-with-or-at-least-k-ii.js)|Medium|
+3099|[Harshad Number](./solutions/3099-harshad-number.js)|Easy|
 3105|[Longest Strictly Increasing or Strictly Decreasing Subarray](./solutions/3105-longest-strictly-increasing-or-strictly-decreasing-subarray.js)|Easy|
 3108|[Minimum Cost Walk in Weighted Graph](./solutions/3108-minimum-cost-walk-in-weighted-graph.js)|Hard|
 3110|[Score of a String](./solutions/3110-score-of-a-string.js)|Easy|

solutions/3099-harshad-number.js

@@ -0,0 +1,22 @@
+/**
+ * 3099. Harshad Number
+ * https://leetcode.com/problems/harshad-number/
+ * Difficulty: Easy
+ *
+ * An integer divisible by the sum of its digits is said to be a Harshad number. You are given
+ * an integer x. Return the sum of the digits of x if x is a Harshad number, otherwise, return -1.
+ */
+
+/**
+ * @param {number} x
+ * @return {number}
+ */
+var sumOfTheDigitsOfHarshadNumber = function(x) {
+  let digitSum = 0;
+  let num = x;
+  while (num > 0) {
+    digitSum += num % 10;
+    num = Math.floor(num / 10);
+  }
+  return x % digitSum === 0 ? digitSum : -1;
+};