in my first round they asked 2 dsa questions and some behavioral questions 1st question was modified version of lru cache.. and 2nd question was top k elements from data stream. behavioral questions are - explain a situation when you show leadership, explain a situation when you are not able to meet the requirement, explain a situation when you failed... prepare them from the view of leadership principals.. tell the answers like story.. make sure it's engaging.

q1) Let's say we are working on a shopping website and we want to analyze non returning users to offer them some promotions to get their attention again.

We know that every user has their unique usernames, so we can track whether they are visiting the website again or not.

For this task we need to implement below methods.

1. newUserLogin(username): This method will be called every time a user logs in
2. getOldestOneTimeVisitingUser(): This method will return the username of the oldest customer who has visited the website only once. Example 1:

newUserLogin(john); newUserLogin(jeff); newUserLogin(jeff); getOldestOneTimeVisitingUser(); should return john

Example 2:

newUserLogin(chriss); newUserLogin(john); newUserLogin(adam); newUserLogin(sandy); getOldestOneTimeVisitingUser(); should return chriss

newUserLogin(chriss); getOldestOneTimeVisitingUser(); should return john

q2) Amazon sells millions of products on its website and for better customer experience we like to show a widget with the "most popular items bought" on the home page.

I'd like you to tell me how you'd go about calculating the top-k popular items sold on Amazon in real time.

Example 1: K = 2 Item bought: 1 --> should return [1] Item bought: 2 --> should return [1,2] Item bought: 3 --> should return [1,3] or [2,3] or [1,2] Item bought: 3 --> should return [1,3] or [2,3] Item bought: 2 --> should return [2,3]