New Problem Solution -"Maximum Number of Balls in a Box"

README.md

@@ -49,6 +49,7 @@ LeetCode
 |1750|[Minimum Length of String After Deleting Similar Ends](https://leetcode.com/problems/minimum-length-of-string-after-deleting-similar-ends/) | [C++](./algorithms/cpp/minimumLengthOfStringAfterDeletingSimilarEnds/MinimumLengthOfStringAfterDeletingSimilarEnds.cpp)|Medium|
 |1749|[Maximum Absolute Sum of Any Subarray](https://leetcode.com/problems/maximum-absolute-sum-of-any-subarray/) | [C++](./algorithms/cpp/maximumAbsoluteSumOfAnySubarray/MaximumAbsoluteSumOfAnySubarray.cpp)|Medium|
 |1748|[Sum of Unique Elements](https://leetcode.com/problems/sum-of-unique-elements/) | [C++](./algorithms/cpp/sumOfUniqueElements/SumOfUniqueElements.cpp)|Easy|
+|1742|[Maximum Number of Balls in a Box](https://leetcode.com/problems/maximum-number-of-balls-in-a-box/) | [C++](./algorithms/cpp/maximumNumberOfBallsInABox/MaximumNumberOfBallsInABox.cpp)|Easy|
 |1736|[Latest Time by Replacing Hidden Digits](https://leetcode.com/problems/latest-time-by-replacing-hidden-digits/) | [C++](./algorithms/cpp/latestTimeByReplacingHiddenDigits/LatestTimeByReplacingHiddenDigits.cpp)|Easy|
 |1734|[Decode XORed Permutation](https://leetcode.com/problems/decode-xored-permutation/) | [C++](./algorithms/cpp/decodeXORedPermutation/DecodeXoredPermutation.cpp)|Medium|
 |1733|[Minimum Number of People to Teach](https://leetcode.com/problems/minimum-number-of-people-to-teach/) | [C++](./algorithms/cpp/minimumNumberOfPeopleToTeach/MinimumNumberOfPeopleToTeach.cpp)|Medium|

algorithms/cpp/maximumNumberOfBallsInABox/MaximumNumberOfBallsInABox.cpp

@@ -0,0 +1,70 @@
+// Source : https://leetcode.com/problems/maximum-number-of-balls-in-a-box/
+// Author : Hao Chen
+// Date   : 2021-03-27
+
+/***************************************************************************************************** 
+ *
+ * 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.
+ * 
+ * Example 1:
+ * 
+ * Input: lowLimit = 1, highLimit = 10
+ * Output: 2
+ * Explanation:
+ * Box Number:  1 2 3 4 5 6 7 8 9 10 11 ...
+ * Ball Count:  2 1 1 1 1 1 1 1 1 0  0  ...
+ * Box 1 has the most number of balls with 2 balls.
+ * 
+ * Example 2:
+ * 
+ * Input: lowLimit = 5, highLimit = 15
+ * Output: 2
+ * Explanation:
+ * Box Number:  1 2 3 4 5 6 7 8 9 10 11 ...
+ * Ball Count:  1 1 1 1 2 2 1 1 1 0  0  ...
+ * Boxes 5 and 6 have the most number of balls with 2 balls in each.
+ * 
+ * Example 3:
+ * 
+ * Input: lowLimit = 19, highLimit = 28
+ * Output: 2
+ * Explanation:
+ * Box Number:  1 2 3 4 5 6 7 8 9 10 11 12 ...
+ * Ball Count:  0 1 1 1 1 1 1 1 1 2  0  0  ...
+ * Box 10 has the most number of balls with 2 balls.
+ * 
+ * Constraints:
+ * 
+ * 	1 <= lowLimit <= highLimit <= 10^5
+ ******************************************************************************************************/
+
+class Solution {
+private:
+    int sum(int n) {
+        int s = 0;
+        for(; n > 0; n /= 10){
+            s += n % 10;
+        }
+        return s;
+    }
+public:
+    int countBalls(int lowLimit, int highLimit) {
+        int cnt[46] ={0}; //10^5 means 9+9+9+9+9 = 45
+        int m = 0;
+        for (int n = lowLimit; n<=highLimit; n++) {
+            int box = sum(n);
+            cnt[box]++;
+            m = max(m, cnt[box]);
+        }
+        return m;
+    }
+};