Amazon| SDE2 | Onsite Loop Interview

Round 1 - Low Level Design

Questions:

1. Tell me about a time when you went above and beyond to serve a customer. Why? How?
2. Tell me about a time when you took an unpopular stance and your team members or manager disagreed. What? How did you navigate?
3. Design Tic Tac Toe.

Candidate's Approach

No approach provided.

Interviewer's Feedback

No feedback provided.

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Round 2 - Hiring Manager - System Design

Questions:

1. Tell me about a time when you had to learn a new skillset beyond the scope of your day-to-day work.
2. Conflict Resolution with manager.
3. Design Instagram.

Candidate's Approach

No approach provided.

Interviewer's Feedback

No feedback provided.

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Round 3 - Coding

Questions:

1. Customer obsession.
2. Dive deep.
3. Medium question, didn't come across in Leetcode but could be solved using a priority queue in under 20 minutes.

Candidate's Approach

No approach provided.

Interviewer's Feedback

No feedback provided.

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Round 4 - Coding

Questions:

1. Deliver under strict deadlines.
2. Tell me about a time when you had to make a decision between long-term value or short-term results.
3. Design a lottery system where a customer can buy a lottery ticket ranging from 1 cent to 100 dollars. At the end of the sale of all lottery tickets, a winner will be chosen randomly, and the chances of winning should be according to the price paid for the ticket; in other words, the one who paid more should have more chances of winning.

import java.util.*;

class LotterySystem {
    private final NavigableMap<Integer, String> ticketMap;
    private final Random random;
    private int totalWeight;

    public LotterySystem() {
        this.ticketMap = new TreeMap<>();
        this.random = new Random();
        this.totalWeight = 0;
    }

    public void buyTicket(String customer, int amount) {
        if (amount < 1 || amount > 10000) {
            throw new IllegalArgumentException("Ticket price must be between 1 cent and 100 dollars");
        }
        totalWeight += amount;
        ticketMap.put(totalWeight, customer);
    }

    public String drawWinner() {
        if (ticketMap.isEmpty()) {
            throw new IllegalStateException("No tickets sold, cannot draw a winner");
        }
        int luckyNumber = random.nextInt(totalWeight) + 1;
        return ticketMap.ceilingEntry(luckyNumber).getValue();
    }

    public static void main(String[] args) {
        LotterySystem lottery = new LotterySystem();
        lottery.buyTicket("Alice", 500); // Alice buys a ticket worth $5.00
        lottery.buyTicket("Bob", 1000); // Bob buys a ticket worth $10.00
        lottery.buyTicket("Charlie", 200); // Charlie buys a ticket worth $2.00
        
        System.out.println("The winner is: " + lottery.drawWinner());
    }
}

Candidate's Approach

Interviewer had a certain solution in mind, struggled a lot to arrive at that, came up with something similar, not sure if this helped.

Interviewer's Feedback

No feedback provided.

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