HackerRank: Input: A bag contains n = 6 items with IDs [1, 1, 1, 2, 2, 3], and m = 2 items can be removed. Output: What is the minimum number of different IDs the final bag can contain? Hacker Rank : You are given a list of students, each associated with a subject. Your goal is to form the maximum number of teams such that:Each team has exactly one student from each subject.A student can only be part of one team. eg : Input: ["Math", "Physics", "History", "Math", "Physics", "History", "Math", "History"] System Design : Design a Comparator that compares two files before process and after processed.