Visa Inc. Software Engineer Internship interview questions

2 medium (string, arrays) and 1 dictionary (hard problem). all leetcode level questions. Interview was in hacker rank with camera on. The Challenge: Design a data structure to store the strings' count with the ability to return the strings with minimum and maximum counts. Implement a class that increments a string's count, decrements a string's count, gets the key with the maximum count, and gets the key with the minimum count—all in \(O(1)\) time complexity.