solves maximum number of balls in a box

Author: anishLearnsToCode

Diff for: README.md

@@ -426,7 +426,7 @@
 | 1725 | [Number Of Rectangles That Can Form The Largest Square](https://leetcode.com/problems/number-of-rectangles-that-can-form-the-largest-square)              |                                                  [![Java](assets/java.png)](src/NumberOfRectanglesThatCanFormTheLargestSquare.java)                                                  |                                                                                                                                   |
 | 1732 | [Find the Highest Altitude](https://leetcode.com/problems/find-the-highest-altitude)                                                                      |                                                             [![Java](assets/java.png)](src/FindTheHighestAltitude.java)                                                              |                                                                                                                                   |
 | 1736 | [Latest Time by Replacing Hidden Digits](https://leetcode.com/problems/latest-time-by-replacing-hidden-digits)                                            |                                                        [![Java](assets/java.png)](src/LatestTimeByReplacingHiddenDigits.java)                                                        |                                                                                                                                   |
-| 1742 | [Maximum Number of Balls in a Box](https://leetcode.com/problems/maximum-number-of-balls-in-a-box)                                                        |                                                                                                                                                                                      |                                                                                                                                   |
+| 1742 | [Maximum Number of Balls in a Box](https://leetcode.com/problems/maximum-number-of-balls-in-a-box)                                                        |                                                           [![Java](assets/java.png)](src/MaximumNumberOfBallsInABox.java)                                                            |                                                                                                                                   |
 | 1748 | [Sum of Unique Elements](https://leetcode.com/problems/sum-of-unique-elements)                                                                            |                                                                                                                                                                                      |                                                                                                                                   |
 | 1752 | [Check if Array Is Sorted and Rotated](https://leetcode.com/problems/check-if-array-is-sorted-and-rotated)                                                |                                                                                                                                                                                      |                                                                                                                                   |
 | 1758 | [Minimum Changes To Make Alternating Binary String](https://leetcode.com/problems/minimum-changes-to-make-alternating-binary-string)                      |                                                                                                                                                                                      |                                                                                                                                   |

Diff for: src/MaximumNumberOfBallsInABox.java

@@ -0,0 +1,22 @@
+import java.util.HashMap;
+import java.util.Map;
+
+public class MaximumNumberOfBallsInABox {
+    public int countBalls(int lowLimit, int highLimit) {
+        final Map<Integer, Integer> boxes = new HashMap<>();
+        for (int ball = lowLimit ; ball <= highLimit ; ball++) {
+            int boxNumber = sumOfDigits(ball);
+            boxes.put(boxNumber, boxes.getOrDefault(boxNumber, 0) + 1);
+        }
+        return boxes.values().stream().max(Integer::compareTo).get();
+    }
+
+    private int sumOfDigits(int n) {
+        int sum = 0;
+        while (n > 0) {
+            sum += n % 10;
+            n /= 10;
+        }
+        return sum;
+    }
+}