Amazon L4 Engineer Interview Questions and Answers

Q1. Print the nodes of a n-ary tree in an arc wise manner as seen from the outside.
Ans. 
Print nodes of n-ary tree in arc wise manner from outside
• Traverse the tree level by level from outside to inside

• Use a queue to keep track of nodes at each level

• Print the nodes at each level in a clockwise or anticlockwise manner
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Q1. Data structure and algorithm
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Q2. Some tricky logical question
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Q3. Stack and queue
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Q4. Some basic question about system Design
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Hackerrank Coding Test, Leetcode medium questions

HLD test, was asked to design an online coding platform like leetcode

Q1. Most interesting project you have worked on
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Q2. How do you handle conflict at workplace
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Some database questions,some java questions .

Q1. What is the difference between javascript and jQuery.
Ans. 
JavaScript is a programming language used for web development, while jQuery is a library built with JavaScript to simplify HTML document traversal and manipulation.
• JavaScript is a programming language, while jQuery is a library written in JavaScript.

• JavaScript can be used for a wide range of tasks, while jQuery is mainly used for DOM manipulation and event handling.

• JavaScript is a core technology for web development, w...read more
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Q2. Define different types of join
Ans. 
Different types of joins are used in SQL to combine rows from two or more tables based on a related column between them.
• Inner Join: Returns rows when there is at least one match in both tables.

• Left Join (or Left Outer Join): Returns all rows from the left table and the matched rows from the right table.

• Right Join (or Right Outer Join): Returns all rows from the right table and the matched rows from the left table.

• Full ...read more
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Q3. Define multithreading concept and exception handling.
Ans. 
Multithreading allows multiple threads to run concurrently, while exception handling deals with errors in a program.
• Multithreading involves running multiple threads simultaneously to improve performance and responsiveness.

• Threads share the same memory space but have their own program counter and registers.

• Exception handling is a mechanism to handle errors or exceptional situations in a program.

• It helps prevent the prog...read more
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Q1. What is distributed system
Ans. 
A distributed system is a collection of independent computers that appear to the users as a single coherent system.
• Consists of multiple computers connected through a network

• Allows for parallel processing and fault tolerance

• Examples include cloud computing, peer-to-peer networks, and distributed databases
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Q2. Jenkins to deploy the automation from git repo, procedure
Ans. 
Use Jenkins pipeline to deploy automation from git repo
• Create a Jenkins pipeline job

• Configure the job to pull code from the git repository

• Define the deployment steps in the Jenkinsfile

• Use Jenkins plugins like Git plugin and Pipeline plugin for automation

• Ensure proper permissions and credentials are set up for accessing the git repo
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Q1. Given array of integer create subarray with sum = 0
Ans. 
Create subarrays with sum = 0 from given array of integers.
• Iterate through the array and keep track of the running sum.

• Store the running sum in a hashmap and check if the current sum - any previous sum equals 0.

• If yes, then the subarray between those two indices has a sum of 0.
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Q2. Left view of binary tree
Ans. 
The left view of a binary tree is the set of nodes visible when the tree is viewed from the left side.
• Traverse the tree in a level order manner and keep track of the first node at each level.

• Use a queue to store nodes at each level and update the left view nodes accordingly.

• Example: For a binary tree with root node 1, left child 2, and right child 3, the left view would be [1, 2].
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45 min round. Similar to Leetcode medium level question.

45 min coding round, 2 question asked

Q1. System design of proximity service
Ans. 
Design a system for proximity service
• Utilize geolocation data to track user locations

• Implement algorithms to calculate proximity between users

• Use real-time updates to notify users of nearby contacts
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Q1. Behavioral questions
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If the cost price of an item is Rs. 150 and the selling price is Rs. 200, what is the profit percentage?

Q1. What is the difference between a stack and a queue? Give an example where you would use each.
Ans. 
A stack is a LIFO data structure while a queue is a FIFO data structure.
• Stack: Last In First Out (LIFO), used in undo/redo functionality, backtracking, and recursion.

• Queue: First In First Out (FIFO), used in job scheduling, breadth-first search, and printing.

• Stack uses push() and pop() operations while queue uses enqueue() and dequeue() operations.
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Q2. What is the difference between a compiler and an interpreter?
Ans. 
A compiler translates the entire program into machine code before execution, while an interpreter translates and executes the program line by line.
• A compiler converts the source code into an executable file, while an interpreter executes the code directly.

• Compilers typically produce faster and more efficient code, while interpreters provide faster development and debugging.

• Examples of compilers include GCC, Clang, and ...read more
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Q3. A compiler is a program that translates the entire source code into machine code before executing it. The source code is fed into the compiler, which analyzes and translates it into an executable file. Thi...read more
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Q1. How do you handle stress and pressure?
Ans. 
I handle stress and pressure by practicing time management, seeking support from colleagues, and maintaining a healthy work-life balance.
• I prioritize tasks and create a schedule to manage my time effectively.

• I communicate with my team and seek their assistance or guidance when needed.

• I engage in stress-relieving activities outside of work, such as exercising or spending time with loved ones.

• I practice mindfulness and d...read more
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