Add solution #1742

Author: JoshCrozier

README.md

@@ -1,4 +1,4 @@
-# 1,513 LeetCode solutions in JavaScript
+# 1,514 LeetCode solutions in JavaScript
 
 [https://leetcodejavascript.com](https://leetcodejavascript.com)
 
@@ -1341,6 +1341,7 @@
 1737|[Change Minimum Characters to Satisfy One of Three Conditions](./solutions/1737-change-minimum-characters-to-satisfy-one-of-three-conditions.js)|Medium|
 1738|[Find Kth Largest XOR Coordinate Value](./solutions/1738-find-kth-largest-xor-coordinate-value.js)|Medium|
 1739|[Building Boxes](./solutions/1739-building-boxes.js)|Hard|
+1742|[Maximum Number of Balls in a Box](./solutions/1742-maximum-number-of-balls-in-a-box.js)|Easy|
 1748|[Sum of Unique Elements](./solutions/1748-sum-of-unique-elements.js)|Easy|
 1749|[Maximum Absolute Sum of Any Subarray](./solutions/1749-maximum-absolute-sum-of-any-subarray.js)|Medium|
 1752|[Check if Array Is Sorted and Rotated](./solutions/1752-check-if-array-is-sorted-and-rotated.js)|Easy|

solutions/1742-maximum-number-of-balls-in-a-box.js

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+/**
+ * 1742. Maximum Number of Balls in a Box
+ * https://leetcode.com/problems/maximum-number-of-balls-in-a-box/
+ * Difficulty: Easy
+ *
+ * You are working in a ball factory where you have n balls numbered from lowLimit up to
+ * highLimit inclusive (i.e., n == highLimit - lowLimit + 1), and an infinite number of
+ * boxes numbered from 1 to infinity.
+ *
+ * Your job at this factory is to put each ball in the box with a number equal to the sum
+ * of digits of the ball's number. For example, the ball number 321 will be put in the
+ * box number 3 + 2 + 1 = 6 and the ball number 10 will be put in the box number 1 + 0 = 1.
+ *
+ * Given two integers lowLimit and highLimit, return the number of balls in the box with
+ * the most balls.
+ */
+
+/**
+ * @param {number} lowLimit
+ * @param {number} highLimit
+ * @return {number}
+ */
+var countBalls = function(lowLimit, highLimit) {
+  const boxCounts = new Map();
+  let result = 0;
+
+  for (let ball = lowLimit; ball <= highLimit; ball++) {
+    const box = sumDigits(ball);
+    const count = (boxCounts.get(box) || 0) + 1;
+    boxCounts.set(box, count);
+    result = Math.max(result, count);
+  }
+
+  return result;
+
+  function sumDigits(num) {
+    let sum = 0;
+    while (num > 0) {
+      sum += num % 10;
+      num = Math.floor(num / 10);
+    }
+    return sum;
+  }
+};