# Interview experience for campus placement for Amazon?

90 minutes in the first round

On Hackerrank, there were 20 multiple-choice questions about aptitude, operating systems, databases, data structures, and algorithms.

There were two questions about coding.

1. O(n) was enough to discover the first non-repeating character of a string.
2. Given an array of integers, calculate the lowest number of members to delete from the array so that the new array’s greatest element is at most twice the minimum. It was necessary to find an O(nlogn) solution.

Second round:

He began with an introduction before diving into the topic and discussing around 15 mints.

Q1. Find the largest loss in buying and selling stocks given a set of stock prices. First, I gave him advice, and then he requested me to code. It was coded.

Q2. Given a list of stations and their distances between them, find the shortest distance between all pairs.

(In O(V3), the Floyd-Warshall algorithm is used.)

3rd round:

Q1. I’ve been asked to shed some light on a few hot technologies.

(I discussed cloud computing, big data, and other topics.) He was impressed because it just took 30 minutes.

Q2: Use the Dictionary

(When I inquired about the basic arrangement, I was told that a large number of terms had already been entered, each with its own definition, synonyms, and antonyms.)

(I began with vector vector text> >, then HashMap, Set >, and finally the RB Tree method.)

4th round:

Q1. Is there a spiral version of Level Order Traversal?

Q2. Join k sorted arrays together.

(Any and all approaches)?

Q3: What is the Binary Tree’s diameter?