The process took 3 weeks. I interviewed at Amazon in Feb 2011
Interview
2 phone Interviews and 1 face to face interview. Interview questions.
What is recall is this
Quickest way to find missing number and missing slot in array of 100 elements
Iterate through the array and compute the sum of all numbers. Now, sum of natural numbers from 1 to N, can be expressed as Nx(N+1)/2. N=100.
Subtract the sum of the array from Nx(N+1)/2, where N=100.
That is the missing number. The empty slot can be detected during the iteration in which the sum is computed.
// will be the sum of the numbers in the array.
int sum = 0;
int idx = -1;
for (int i = 0; i < arr.length; i++) {
if (arr[i] == 0) {
idx = i;
} else {
sum += arr[i];
}
}
// the total sum of numbers between 1 and arr.length.
int total = (arr.length + 1) * arr.length / 2;
System.out.println("missing number is: " + (total - sum) + " at index " + idx);
Great interview process with three rounds, including a technical assessment and a technical interview. The interviewers were professional and supportive throughout the process. The questions mainly focused on DSA, problem-solving, and core technical concepts. The discussions were engaging and provided a good opportunity to demonstrate technical skills. Overall, the process was well-structured, smooth, transparent, and a very positive experience.
I applied through college or university. I interviewed at Amazon (Dublin, Dublin)
Interview
Online techincal assessment. Had to screen share and complete basic coding tasks similar to Leet Code. Could choose a language of your choice. Overall a very fair system and judged based on merit.
Interview questions [1]
Question 1
Technical assessment so a basic leet code style question about reversing the orders of long numerical strings.
Loop — 4 rounds, all on the same day
Round 1 — Coding (DSA)
Interviewer was a senior SDE, very friendly.
Warm-up + behavioral: "Tell me about a time you took ownership of something outside your responsibilities."
Main question: Given a list of meeting intervals, find the minimum number of conference rooms required. I used a heap. He then asked a follow-up: what if meetings could be reassigned to minimize total idle time? We discussed approaches but didn't fully code it.
He cared a lot about how I talked through edge cases out loud.
Round 2 — Coding + Problem Solving
LP question: "Describe a situation where you disagreed with a teammate."
Coding: LRU Cache implementation from scratch. I used a hashmap + doubly linked list. He pushed on thread-safety and what happens at capacity 0.
Round 3 — Behavioral (Bar Raiser)
This was the toughest round — no coding, all Leadership Principles, very deep STAR-format probing.
Questions I got:
"Tell me about a time you failed and what you learned."
"A time you had to deliver something with a tight deadline and limited information."
The bar raiser kept drilling: "What was your specific contribution?" "What would you do differently?" "What data did you use?" Have 6–8 strong stories ready with metrics.
Round 4 — Low-Level Design
Design: Design a parking lot system (classes, vehicle types, spot allocation, pricing). Then he asked me to code the findSpot() and releaseSpot() methods.
Interview questions [1]
Question 1
Most coding questions were LeetCode Medium. Common themes: graphs, heaps, sliding window, hashmaps, and LRU/design., system design,