Atlassian Front end Engineer Interview Questions and Answers for Experienced

Q1. What is difference between abstract class and interface?
Ans. 
Abstract class can have implementation while interface cannot. Classes can implement multiple interfaces but only one abstract class.
• Abstract class can have constructors while interface cannot.

• Abstract class can have non-abstract methods while interface cannot.

• Interfaces are used for full abstraction while abstract classes are used for partial abstraction.

• Example: Abstract class - Animal with method eat() and subclass ...read more
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Round duration - 120 Minutes
Round difficulty - Medium

The test included MCQ questions from SQL, Linux Commands, C/C++ programming, Logical Reasoning, Aptitude questions. The other section was the coding round, where 2 SQL queries and 2 coding questions were there.

Q1. 
Subarray with Equal Occurrences Problem Statement
You are provided with an array/list ARR of length N containing only 0s and 1s. Your goal is to determine the number of non-empty subarrays where the numbe...read more
Ans. 
Count the number of subarrays where the number of 0s is equal to the number of 1s in a given array of 0s and 1s.
• Iterate through the array and keep track of the count of 0s and 1s encountered so far.

• Use a hashmap to store the count of 0s and 1s encountered at each index.

• For each index, check if the count of 0s is equal to the count of 1s encountered so far and update the result accordingly.
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Q2. 
Pythagorean Triplets Detection
Determine if an array contains a Pythagorean triplet by checking whether there are three integers x, y, and z such that x² + y² = z² within the array.
Input:
The first lin...read more
Ans. 
Detect if an array contains a Pythagorean triplet by checking if there are three integers x, y, and z such that x^2 + y^2 = z^2.
• Iterate through all possible triplets of numbers in the array and check if they form a Pythagorean triplet.

• Use a nested loop to generate all possible combinations of three numbers from the array.

• Check if the sum of squares of two numbers is equal to the square of the third number for each trip...read more
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Round duration - 50 Minutes
Round difficulty - Medium

This was a standard DSA round where I was asked to solve 2 questions and also code it in a production ready manner . At the end I was also asked some questions related to Linux and SQL . I was tested on some basic commands of Linux .

Q1. 
Palindromic Substrings Problem Statement
Given a string S, your task is to return all distinct palindromic substrings of the given string in alphabetical order.
Explanation:
A string is considered a pal...read more
Ans. 
Return all distinct palindromic substrings of a given string in alphabetical order.
• Iterate through all possible substrings of the given string.

• Check if each substring is a palindrome.

• Store distinct palindromic substrings in alphabetical order.
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Q2. 
Swap Two Numbers Problem Statement
Given two integers a and b, your task is to swap these numbers and output the swapped values.
Input:
The first line contains a single integer 't', representing the num...read more
Ans. 
Swap two integers 'a' and 'b' and output the swapped values.
• Create a temporary variable to store one of the integers before swapping.

• Swap the values of 'a' and 'b' using the temporary variable.

• Output the swapped values of 'a' and 'b'.
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Q3. What is meant by normalization and denormalization?
Ans. 
Normalization is the process of organizing data in a database to reduce redundancy and improve data integrity, while denormalization is the process of intentionally adding redundancy to improve query performance.
• Normalization involves breaking down a table into smaller tables and defining relationships between them to reduce redundancy and dependency.

• Denormalization involves combining tables or adding redundant data to...read more
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Round duration - 60 Minutes
Round difficulty - Medium

This was a DS/Algo + Core round where I was asked questions related to DBMS , SQL queries and Linux Commands . The first question was of DSA and I was able to code it preety fast . I was also asked to execute some SQL queries on my laptop.
Overall , this round went good according to my opinion.

Q1. 
Anagram Pairs Verification Problem
Your task is to determine if two given strings are anagrams of each other. Two strings are considered anagrams if you can rearrange the letters of one string to form the...read more
Ans. 
Check if two strings are anagrams of each other by comparing their sorted characters.
• Sort the characters of both strings and compare them.

• Use a dictionary to count the frequency of characters in each string and compare the dictionaries.

• Ensure both strings have the same length before proceeding with comparison.

• Handle edge cases like empty strings or strings with different lengths.
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Q2. How would you delete duplicate emails from a database using SQL?
Ans. 
Use SQL query with GROUP BY and HAVING clause to delete duplicate emails from a database.
• Use GROUP BY clause to group emails together

• Use HAVING clause to filter out groups with more than one email

• Use DELETE statement to remove duplicate emails
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Q3. What is the difference between the DELETE and TRUNCATE commands in a DBMS?
Ans. 
DELETE removes specific rows from a table, while TRUNCATE removes all rows and resets auto-increment values.
• DELETE is a DML command, while TRUNCATE is a DDL command.

• DELETE can be rolled back, while TRUNCATE cannot be rolled back.

• DELETE triggers ON DELETE triggers, while TRUNCATE does not trigger any triggers.

• DELETE is slower as it maintains logs, while TRUNCATE is faster as it does not maintain logs.

• Example: DELETE FRO...read more
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Round duration - 30 Minutes
Round difficulty - Easy

This was a typical HR round with some standard Behavioral questions .

Q1. What is something about you that is not included in your resume?
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Q2. Why do you want to work at Amdocs?
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Round duration - 45 minutes
Round difficulty - Medium

Technical Interview round with questions on DSA.

Q1. 
Reverse Words in a String: Problem Statement
You are given a string of length N. Your task is to reverse the string word by word. The input may contain multiple spaces between words and may have leading o...read more
Ans. 
Reverse words in a string while handling leading, trailing, and multiple spaces.
• Split the input string by spaces to get individual words

• Reverse the order of the words

• Join the reversed words with a single space in between

• Handle leading, trailing, and multiple spaces appropriately
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Q2. 
Reverse a Stack Using Recursion
You are given a stack of integers. Your task is to reverse the stack using recursion without using any extra space other than the internal stack space used due to recursion...read more
Ans. 
Reverse a stack using recursion without using any extra space other than the internal stack space.
• Use recursion to pop all elements from the original stack and store them in function call stack.

• Once the stack is empty, push the elements back in reverse order.

• Base case of recursion should be when the original stack is empty.
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Round duration - 45 minutes
Round difficulty - Medium

Technical Interview round with questions on DSA.

Q1. 
Convert a Binary Tree to its Mirror Tree
Given a binary tree, convert this binary tree into its mirror tree. A binary tree is a tree in which each parent node has at most two children. The mirror of a bin...read more
Ans. 
Convert a binary tree to its mirror tree by interchanging left and right children of all non-leaf nodes.
• Traverse the binary tree in a recursive manner.

• Swap the left and right children of each non-leaf node.

• Continue this process until all nodes have been processed.
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Q2. 
Remove Nth Node from End of Linked List
You are given a singly linked list with 'N' nodes, each containing integer data, and an integer 'K'. Your goal is to remove the 'K'th node counting from the end of ...read more
Ans. 
Remove the Kth node from the end of a singly linked list.
• Use two pointers approach to find the Kth node from the end.

• Handle edge cases like removing the head node or removing the last node.

• Update the pointers to remove the Kth node and reconnect the list.
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Round duration - 30 minutes
Round difficulty - Easy

Typical Managerial round.