Facebook Interview Question

Got the following question: You have two lists: user_id 1, user_id 2, timestamp accepted=([1,2,"2020-01-01"],[3,2,"2020-01-02"],[2,1,"2020-02-02"],...) removed=([2,1,"2020-01-03"],[2,3,"2020-01-05"],[2,1,"2020-04-02"]..) The accepted list is the friendships which were accepted, while removed are the opposite. Create a new list which outputs...