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Facebook Software Developer Interview Questions and Answers for Freshers
8 Interview questions
Search In Rotated Sorted Array Problem Statement
Given a rotated sorted array ARR of size 'N' and an integer 'K', determine the index at which 'K' is present in the array.
Note:
1. If 'K' is not present ...Given a rotated sorted array, find the index of a given integer 'K'.
Use binary search to find the pivot point where the array is rotated.
Then perform binary search on the appropriate half of the array to find 'K'.
Handle cases where 'K' is not present in the array by returning -1.
Rank from Stream Problem Statement
Given an array of integers ARR and an integer K, determine the rank of the element ARR[K].
Explanation:
The rank of any element in ARR is defined as the number of eleme...
Given an array and an index, find the number of elements smaller than the element at that index appearing before it in the array.
Iterate through the array up to index K and count the number of elements smaller than ARR[K].
Return the count as the rank of ARR[K].
Handle edge cases like empty array or invalid index K.
LRU Cache Design Question
Design a data structure for a Least Recently Used (LRU) cache that supports the following operations:
1. get(key) - Return the value of the key if it exists in the cache; otherwi...
Design a Least Recently Used (LRU) cache data structure that supports get and put operations with capacity constraint.
Implement a doubly linked list to maintain the order of recently used keys.
Use a hashmap to store key-value pairs for quick access.
Update the order of keys in the linked list on get and put operations.
Evict the least recently used key when the cache reaches its capacity.
Merge Intervals Problem Statement
You are provided with 'N' intervals, each containing two integers denoting the start time and end time of the interval.
Your task is to merge all overlapping intervals an...
Merge overlapping intervals and return sorted list of merged intervals.
Sort the intervals based on start times.
Iterate through intervals and merge overlapping intervals.
Return the merged intervals in sorted order.
Path Counting in Directed Graph
Given a directed graph with a specified number of vertices V and edges E, your task is to calculate the total number of distinct paths from a given source node S to all oth...
Calculate the total number of distinct paths from a given source node to all other nodes in a directed graph.
Use dynamic programming to keep track of the number of paths from the source node to each node in the graph.
Consider using modular arithmetic to handle large numbers and prevent overflow.
Start by initializing the number of paths from the source node to itself as 1.
Iterate through the edges of the graph and ...
Longest Increasing Subsequence Problem Statement
Given an array of integers with 'N' elements, determine the length of the longest subsequence where each element is greater than the previous element. This ...
Find the length of the longest strictly increasing subsequence in an array of integers.
Use dynamic programming to solve this problem efficiently.
Initialize an array to store the length of the longest increasing subsequence ending at each index.
Iterate through the array and update the length of the longest increasing subsequence for each element.
Return the maximum value in the array as the result.
Course Schedule II Problem Statement
You are provided with a number of courses 'N', some of which have prerequisites. There is a matrix named 'PREREQUISITES' of size 'M' x 2. This matrix indicates that for...
Given courses with prerequisites, determine a valid order to complete all courses.
Use topological sorting to find a valid order of courses.
Create a graph with courses as nodes and prerequisites as edges.
Start with courses that have no prerequisites and remove them from the graph.
Continue this process until all courses are taken or there are no valid courses left.
If there is a cycle in the graph, it is impossible t...
Longest Route Problem Statement
Given a 2-dimensional binary matrix called Mat of size N x M that consists solely of 0s and 1s, find the length of the longest path from a specified source cell to a destinat...
Find the length of the longest path from a source cell to a destination cell in a binary matrix.
Use depth-first search (DFS) to explore all possible paths from source to destination.
Keep track of visited cells to avoid revisiting them.
Return the length of the longest path found, or -1 if no path exists.
Facebook Software Developer Interview Experiences for Freshers
2 interviews found
Anonymous
I applied via LinkedIn and was interviewed in Jul 2024. There was 1 interview round.
(2 Questions)
- Q1. Why you want to join facebook?
- Ans.
I want to join Facebook because of its innovative technology, global impact, and opportunities for growth.
Innovative technology: Facebook is known for its cutting-edge technology and constant innovation.
Global impact: Working at Facebook would allow me to contribute to a platform that connects billions of people worldwide.
Opportunities for growth: Facebook offers a dynamic and fast-paced work environment with ample opp...
- Q2. Whats the best feature you like in Facebook?
- Ans.
I appreciate the personalized news feed feature on Facebook.
Personalized news feed shows content based on user interests
Helps users stay updated on relevant information
Allows users to engage with content they are interested in
I appeared for an interview before Dec 2020.
(2 Questions)
Round duration - 90 minutes
Round difficulty - Hard
This was an online coding round where we were supposed to solve 2 questions under 90 minutes . Both the questions in my set were related to Graphs and were quite tricky and heavy to implement.
- Q1.
Path Counting in Directed Graph
Given a directed graph with a specified number of vertices
Vand edgesE, your task is to calculate the total number of distinct paths from a given source nodeSto all ot... - Ans.
Calculate the total number of distinct paths from a given source node to all other nodes in a directed graph.
Use dynamic programming to keep track of the number of paths from the source node to each node in the graph.
Consider using modular arithmetic to handle large numbers and prevent overflow.
Start by initializing the number of paths from the source node to itself as 1.
Iterate through the edges of the graph and updat...
- Q2.
Course Schedule II Problem Statement
You are provided with a number of courses 'N', some of which have prerequisites. There is a matrix named 'PREREQUISITES' of size 'M' x 2. This matrix indicates that fo...
- Ans.
Given courses with prerequisites, determine a valid order to complete all courses.
Use topological sorting to find a valid order of courses.
Create a graph with courses as nodes and prerequisites as edges.
Start with courses that have no prerequisites and remove them from the graph.
Continue this process until all courses are taken or there are no valid courses left.
If there is a cycle in the graph, it is impossible to com...
(2 Questions)
Round duration - 60 Minutes
Round difficulty - Medium
This was a Data Structures and Algorithms round with some standard questions . I was expected to come up with an
efficient approach and code it as well .
- Q1.
Merge Intervals Problem Statement
You are provided with 'N' intervals, each containing two integers denoting the start time and end time of the interval.
Your task is to merge all overlapping intervals a...
- Ans.
Merge overlapping intervals and return sorted list of merged intervals.
Sort the intervals based on start times.
Iterate through intervals and merge overlapping intervals.
Return the merged intervals in sorted order.
- Q2.
Longest Route Problem Statement
Given a 2-dimensional binary matrix called
Matof size N x M that consists solely of 0s and 1s, find the length of the longest path from a specified source cell to a destina... - Ans.
Find the length of the longest path from a source cell to a destination cell in a binary matrix.
Use depth-first search (DFS) to explore all possible paths from source to destination.
Keep track of visited cells to avoid revisiting them.
Return the length of the longest path found, or -1 if no path exists.
(2 Questions)
Round duration - 50 Minutes
Round difficulty - Medium
This was also a DSA round where I was asked to code only one of the questions but I eventually ended up coding both
as I had some spare time and explained my approches very smoothly to the interviewer . This round went preety well .
- Q1.
Longest Increasing Subsequence Problem Statement
Given an array of integers with 'N' elements, determine the length of the longest subsequence where each element is greater than the previous element. This...
- Ans.
Find the length of the longest strictly increasing subsequence in an array of integers.
Use dynamic programming to solve this problem efficiently.
Initialize an array to store the length of the longest increasing subsequence ending at each index.
Iterate through the array and update the length of the longest increasing subsequence for each element.
Return the maximum value in the array as the result.
- Q2.
Search In Rotated Sorted Array Problem Statement
Given a rotated sorted array
ARRof size 'N' and an integer 'K', determine the index at which 'K' is present in the array.Note:
1. If 'K' is not present... - Ans.
Given a rotated sorted array, find the index of a given integer 'K'.
Use binary search to find the pivot point where the array is rotated.
Then perform binary search on the appropriate half of the array to find 'K'.
Handle cases where 'K' is not present in the array by returning -1.
(2 Questions)
Round duration - 50 Minutes
Round difficulty - Medium
This was also a DSA round with 2 questions of Medium to Hard difficulty . I was expected to follow some clean code and OOPS principles to write the code in this round .
- Q1.
Rank from Stream Problem Statement
Given an array of integers
ARRand an integerK, determine the rank of the elementARR[K].Explanation:
The rank of any element in
ARRis defined as the number of elem... - Ans.
Given an array and an index, find the number of elements smaller than the element at that index appearing before it in the array.
Iterate through the array up to index K and count the number of elements smaller than ARR[K].
Return the count as the rank of ARR[K].
Handle edge cases like empty array or invalid index K.
- Q2.
LRU Cache Design Question
Design a data structure for a Least Recently Used (LRU) cache that supports the following operations:
1.
get(key)- Return the value of the key if it exists in the cache; otherw... - Ans.
Design a Least Recently Used (LRU) cache data structure that supports get and put operations with capacity constraint.
Implement a doubly linked list to maintain the order of recently used keys.
Use a hashmap to store key-value pairs for quick access.
Update the order of keys in the linked list on get and put operations.
Evict the least recently used key when the cache reaches its capacity.
Interview Preparation Tips
Tip 1 : Must do Previously asked Interview as well as Online Test Questions.
Tip 2 : Go through all the previous interview experiences from Codestudio and Leetcode.
Tip 3 : Do at-least 2 good projects and you must know every bit of them.
Tip 1 : Have at-least 2 good projects explained in short with all important points covered.
Tip 2 : Every skill must be mentioned.
Tip 3 : Focus on skills, projects and experiences more.
Skills evaluated in this interview
Top trending discussions
Interview questions from similar companies
I appeared for an interview before Dec 2015.
Interview Questionnaire
2 Questions
- Q1. 1 question from basic data structures and algorithms The question was similar to the one in the given link- -----/
- Q2. Why do you want to join the company?
- Ans.
I am excited to join the company because of its reputation for innovation and commitment to employee growth.
I am impressed by the company's track record of developing cutting-edge software solutions.
I appreciate the company's focus on fostering a culture of learning and development.
I am excited about the opportunity to work with a talented team of developers and contribute to the company's success.
I believe that the co...
Interview Preparation Tips
Experience: Resumes were shortlisted with a short aptitude round where we are asked basic questions about databases, basic programming(C and C ++ questions)
Round: Technical Interview
Experience: The questions were asked were simple - related to arrays and data structures. Some questions were asked regarding my resume and projects.
Tips: Be thorough with geeksForGeeks, and your projects.
Round: HR Interview
Experience: I told him how I found the story of the founder of Infoedge very inspiring.
Tips: This round should be more simpler , be prepared with why you want to join the company and general HR questions
Skills: Basic C/C++, Programming Skills In Any Language Like C
College Name: IIIT Allahabad
Interview Preparation Tips
Experience: Ques will be based on arrays( duplicate element, missing element in 1 to n array), link list(reverse, remove loop, middle node etc), Hashing, sql join, normalisation, indexing in sql, singlton pattern and sorting and searching.
Tips: Focus will remain on algorithms. Whatever program they will ask to write, they will also ask to optimize the solution.
Skill Tips: Puzzle on mislabled jar, odd weight ball. As I had exp in Java, so some more que on Java, java script and web technology. All you need in interview is to be confident and show your interest in web domain.
Skills: Java, Data structure, Algorithm
College Name: NA
Interview Questionnaire
10 Questions
- Q1. What do you do when your schedule is interrupted? How you handle it?
- Ans.
I prioritize tasks, communicate effectively, and adapt my plans to manage interruptions while maintaining productivity.
Assess the interruption: Determine its urgency and importance. For example, if a team member needs immediate help, I prioritize that.
Reorganize my tasks: I create a new plan that accommodates the interruption while ensuring critical deadlines are met.
Communicate with stakeholders: I inform my team or m...
- Q2. PreOrder traversal without recursion?
- Ans.
PreOrder traversal without recursion is done using a stack to simulate the function call stack.
Create an empty stack and push the root node onto it.
While the stack is not empty, pop a node from the stack and process it.
Push the right child of the popped node onto the stack if it exists.
Push the left child of the popped node onto the stack if it exists.
- Q3. Build a bst out of the unsorted array by looping over the array and inserting each element to the tree?
- Ans.
Yes
Create an empty binary search tree (BST)
Loop over the unsorted array
For each element, insert it into the BST using the appropriate insertion logic
Repeat until all elements are inserted
The resulting BST will be built from the unsorted array
- Q4. Find 2 elements in array whose sum is equal to given number?
- Ans.
The question asks to find two elements in an array whose sum is equal to a given number.
Iterate through the array and for each element, check if the difference between the given number and the current element exists in the array.
Use a hash set to store the elements as you iterate through the array for efficient lookup.
Return the pair of elements if found, otherwise return a message indicating no such pair exists.
- Q5. How many types of trigger?
- Ans.
There are two types of triggers: DML triggers and DDL triggers.
DML triggers are fired in response to DML (Data Manipulation Language) statements like INSERT, UPDATE, DELETE.
DDL triggers are fired in response to DDL (Data Definition Language) statements like CREATE, ALTER, DROP.
Examples: A DML trigger can be used to log changes made to a table, while a DDL trigger can be used to enforce certain rules when a table is alt...
- Q6. Can trigger be used with select statement?
- Ans.
Yes, triggers can be used with select statements in SQL.
Triggers are database objects that are automatically executed in response to certain events, such as insert, update, or delete operations.
While triggers are commonly used with insert, update, and delete statements, they can also be used with select statements.
Using triggers with select statements allows you to perform additional actions or validations before or af...
- Q7. Indexing in mysql? How many types of indexing in mysql?
- Ans.
Indexing in MySQL improves query performance. There are several types of indexing in MySQL.
Indexes are used to quickly locate data without scanning the entire table.
Types of indexing in MySQL include B-tree, hash, full-text, and spatial indexes.
B-tree indexes are the most common and suitable for most use cases.
Hash indexes are used for exact match lookups.
Full-text indexes are used for searching text-based data efficie...
- Q8. Engines in mysql?
- Ans.
Engines in MySQL are the underlying software components that handle storage, indexing, and querying of data.
MySQL supports multiple storage engines, each with its own strengths and features.
Some commonly used engines in MySQL are InnoDB, MyISAM, and Memory.
InnoDB is the default engine in MySQL and provides support for transactions and foreign keys.
MyISAM is known for its simplicity and speed but lacks transaction suppo...
- Q9. Singlton pattern?
- Ans.
The Singleton pattern ensures a class has only one instance and provides a global point of access to it.
Restricts instantiation of a class to a single object.
Useful for managing shared resources, like database connections.
Implemented using private constructors and static methods.
Example in Java: public class Singleton { private static Singleton instance; private Singleton() {} public static Singleton getInstance() { if...
- Q10. Can a constructor be private?
- Ans.
Yes, a constructor can be private.
A private constructor can only be accessed within the class itself.
It is often used in singleton design pattern to restrict object creation.
Private constructors are also useful for utility classes that only contain static methods.
Interview Preparation Tips
College Name: na
Skills evaluated in this interview
I appeared for an interview before Dec 2020.
(1 Question)
Round duration - 90 minutes
Round difficulty - Easy
Myntra had conducted a coding test on campus before the start of the placement season with 2 questions, one on stack and other on DP.
Tips : For the test, the DP question asked was pretty standard, on Longest Common Subsequence. The question on stacks, I don't remember what it was but it was also pretty straight forward. For the test, I would recommend to solve problem from GFG. If they do come to resume shortlisting, they are looking for people who have done good projects and internships.
- Q1.
Longest Common Subsequence Problem Statement
Given two strings
STR1andSTR2, determine the length of their longest common subsequence.A subsequence is a sequence that can be derived from another sequen...
- Ans.
The task is to find the length of the longest common subsequence between two given strings.
Implement a function to find the longest common subsequence between two strings.
Use dynamic programming to solve this problem efficiently.
Iterate through the strings and build a matrix to store the lengths of common subsequences.
Return the length of the longest common subsequence found.
(1 Question)
Round duration - 60 minutes
Round difficulty - Easy
The interview started off with questions on my general interest in Software Development. The first round had two coding questions, I was supposed to write the code on paper.
For the questions, they asked me to code the solution first. And then gave a specific input and asked me to demonstrate step by step in my code, how it would lead to the correct answer.
Tips: It's ok if you can't code a general solution, if you can write a code which works for the particular input they have given then also it's ok with them. But be thorough with Data structures.
- Q1.
Add Two Numbers as Linked Lists
You are given two singly linked lists, where each list represents a positive number without any leading zeros.
Your task is to add these two numbers and return the sum as ...
- Ans.
Add two numbers represented as linked lists and return the sum as a linked list.
Traverse both linked lists simultaneously while keeping track of carry from previous sum
Create a new linked list to store the sum, updating the value and carry as needed
Handle cases where one linked list is longer than the other by adding remaining digits with carry
(3 Questions)
Round duration - 60 minutes
Round difficulty - Medium
I wasn't asked to write any code in this interview. They asked me some questions on Machine Learning, because of my projects in them. Then they asked me if I knew graph algorithms. Since I knew BFS and DFS, I told them. They asked the difference between the two. Then they asked me if I knew how to find the shortest distance between two points in a graph. I didn't know Dijkstra's properly but I knew it worked on the greedy approach so was able to tell that. Then they asked me how would I find the second shortest path. I tried to answer it with the same greedy approach, but couldn't arrive at the complete solution.
Tips: They ask a tough theoretical question. It's ok if you don't know the answer, they only look for your approach.
- Q1.
BFS Traversal in a Graph
Given an undirected and disconnected graph G(V, E) where V vertices are numbered from 0 to V-1, and E represents edges, your task is to output the BFS traversal starting from the ...
- Ans.
BFS traversal in a disconnected graph starting from vertex 0.
Use a queue to keep track of nodes to visit next in BFS traversal
Start traversal from vertex 0 and explore its neighbors first
Continue exploring neighbors level by level until all nodes are visited
Ensure to print connected nodes in numerical sort order
- Q2.
DFS Traversal Problem Statement
Given an undirected and disconnected graph
G(V, E), whereVis the number of vertices andEis the number of edges, the connections between vertices are provided in the 'GR... - Ans.
DFS traversal to find connected components in an undirected and disconnected graph.
Perform DFS traversal on each vertex to find connected components
Maintain a visited array to keep track of visited vertices
Print the vertices of each connected component in ascending order
- Q3.
Dijkstra's Shortest Path Problem
Given an undirected graph with ‘V’ vertices (labeled 0, 1, ... , V-1) and ‘E’ edges, where each edge has a weight representing the distance between two connected nodes (X,...
- Ans.
Dijkstra's algorithm is used to find the shortest path from a source node to all other nodes in a graph with weighted edges.
Implement Dijkstra's algorithm to find the shortest path distances from the source node to all other nodes in the graph.
Use a priority queue to efficiently select the next node with the shortest distance.
Update the distances of neighboring nodes based on the current node's distance and edge weight...
Interview Preparation Tips
Tip 1 : Be thorough with Data Structures and Algorithms and also with your resume.
Tip 2 : Must do Previously asked Interview as well as Online Test Questions.
Tip 3 : Go through all the previous interview experiences from Codestudio and Leetcode.
Tip 4 : Do at-least 2 good projects and you must know every bit of them.
Tip 1 : Have at-least 2 good projects explained in short with all important points covered.
Tip 2 : Every skill must be mentioned.
Tip 3 : Focus on skills, projects and experiences more.
Skills evaluated in this interview
Thommandru Vishnu
Interview Questionnaire
9 Questions
- Q1. All the leaf nodes of tree are doubly linked,print only the leaf nodes of a tree
- Ans.
Print only the leaf nodes of a doubly linked tree.
Traverse the tree and check if a node has no children and both left and right pointers are null.
If yes, then it is a leaf node and print it.
If no, then continue traversing the tree.
Use recursion to traverse the tree in a depth-first manner.
- Q2. LRU page Replacement Algorithm for large data
- Ans.
LRU page replacement algorithm is used to replace the least recently used page in memory with a new page.
LRU stands for Least Recently Used
It is a cache eviction algorithm
It is used to manage memory in operating systems
It works by keeping track of the pages that are used recently and the ones that are not
When a new page is to be loaded into memory, the algorithm checks which page has not been used for the longest time ...
- Q3. Given a linked list with 2 parameters m,n. Now start reversing the m nodes and leave n nodes and continue it till u reach the end
- Ans.
Reverse m nodes and leave n nodes in a linked list till the end.
Traverse the linked list till m nodes and reverse them
Traverse n nodes and continue reversing m nodes
Repeat the above step till the end of the linked list
Handle edge cases like m or n being greater than the length of the linked list
- Q4. Inorder Traversal of a tree
- Ans.
Inorder traversal is a way of visiting all nodes in a binary tree by visiting the left subtree, then the root, and then the right subtree.
Start at the root node
Traverse the left subtree recursively
Visit the root node
Traverse the right subtree recursively
Repeat until all nodes have been visited
- Q5. Inorder Travesal of a tree without recursion(write the code)
- Ans.
Inorder traversal of a tree without recursion
Create an empty stack and initialize current node as root
Push the current node to stack and set current = current.left until current is NULL
If current is NULL and stack is not empty, pop the top item from stack, print it and set current = popped_item.right
Repeat step 2 and 3 until stack is empty
- Q6. Given an array of numbers in which duplicates are there and one triplicate is there. find that number
- Ans.
Find the triplicate number in an array of duplicates.
Iterate through the array and keep track of the frequency of each number.
Return the number that appears three times.
If no number appears three times, return null.
- Q7. Explain all the serach algorithm you know with space and Time complexities
- Ans.
Explanation of search algorithms with their space and time complexities.
Linear Search - O(n) time complexity, O(1) space complexity
Binary Search - O(log n) time complexity, O(1) space complexity
Jump Search - O(√n) time complexity, O(1) space complexity
Interpolation Search - O(log log n) time complexity, O(1) space complexity
Exponential Search - O(log n) time complexity, O(1) space complexity
Fibonacci Search - O(log n) ...
- Q8. Given a situation and asks you which search algorithm suits the best in that situation
- Ans.
Choosing the right search algorithm depends on data structure, size, and specific requirements like speed or memory usage.
Binary Search: Efficient for sorted arrays, O(log n) time complexity. Example: Finding a number in a sorted list.
Linear Search: Simple and works on unsorted arrays, O(n) time complexity. Example: Searching for a name in an unsorted list.
Depth-First Search (DFS): Suitable for tree/graph traversal, ex...
- Q9. Given an array of length n and in which numbers from 1-n will be there and each number can repeat any number of times find out which repeated more number of times
- Ans.
Find the most repeated number in an array of length n with numbers 1-n.
Create a dictionary to store the count of each number in the array
Iterate through the array and update the count in the dictionary
Find the key with the highest count in the dictionary
Interview Preparation Tips
Experience: Basically, it's not resume shortlist, it's a 9 pointer shortlist
Round: Test
Experience: The Entire Test is held in HackerRank Platform. it has
2 coding questions (one easy and one medium)
2 output questions(medium)
2 Aptitude(easy)
1 general Computer science(medium)
it took me 30 min for each coding questions.I was not known that general question is related to bash commands.
Tips: Practice the Warmup questions in Hacker Rank.
Do some Basic aptitude questions.
Thorough with the basic c and c++ concepts
Duration: 120 minutes
Total Questions: 7
Round: Technical Interview
Experience: It's completely around the data structures. The questions are a bit tricky but once u think without any tension u can get through easily. The interviewer is helpful and gives u few hints if u catch them at the right point of time u got it.There are 2 more questions which I haven't mentioned.
Tips: got through Data Structures and Algorithms Made Easy by Narasimha Karumanchi. It's a best book for the interviews.
Round: Technical Interview
Experience: The interviewer asked to put everything on the blackboard and write down the code of each and everything.
Tips: Go to the website -----/ and study all the interview questions and modules
Round: HR Interview
Experience: It's Technical+ HR interview all the technical questions went around resume. it went around 45 minutes they are very particular about what you wrote in the resume.HR questions are general like
whats your future plans
where will u see yourself in the office after 5 years?
Tips: please make sure that whatever you write in resume should be known to you very well.Don't write false things about yourself.And make sure you know completely about the projects you are going to write in resume(atleast the part you worked)
General Tips: Be sure of what you are saying. Don't be tensed and answer to your best.
Skills: Programming, Data Structures
College Name: VIT VELLORE
Skills evaluated in this interview
Interview Questionnaire
10 Questions
- Q1. Change Binary tree so that parent node is the sum of root nodes
- Ans.
Change binary tree to make parent node the sum of root nodes
Traverse the tree in post-order
For each node, update its value to the sum of its children
Return the updated root node
- Q2. Reverse a linkedlist ?
- Ans.
Reverse a linkedlist by changing the direction of pointers.
Iterate through the linkedlist and change the direction of pointers.
Keep track of previous, current and next nodes.
Set the next pointer of current node to previous node.
Move to next node and repeat until end of list is reached.
- Q3. Given an array of +ve and -ve numbers , have to rearrange them ( like +ve numbers to left and -ve numbers to right of the array)
- Ans.
Rearrange an array of positive and negative numbers with positive numbers on the left and negative numbers on the right.
Create two empty arrays, one for positive numbers and one for negative numbers
Loop through the original array and add positive numbers to the positive array and negative numbers to the negative array
Concatenate the positive and negative arrays to create the rearranged array
- Q4. Singleton pattern, observer pattern?
- Q5. String pool and how garbage collection functionality works?
- Ans.
String pool is a cache of string literals in memory. Garbage collection frees up memory by removing unused objects.
String pool is a cache of string literals in memory
Strings are immutable and can be shared among multiple objects
Garbage collection removes unused objects to free up memory
String objects that are no longer referenced are eligible for garbage collection
- Q6. HashMap , how can you synchronize ?
- Ans.
Synchronizing a HashMap ensures thread safety when multiple threads access it concurrently.
Use Collections.synchronizedMap(): Wrap the HashMap with this method to create a synchronized version.
Example: Map<String, String> syncMap = Collections.synchronizedMap(new HashMap<>());
Use ConcurrentHashMap: This is a thread-safe alternative to HashMap that allows concurrent access.
Example: ConcurrentHashMap<Strin...
- Q7. Process vs Thread differences and synchronization,deadlock examples?
- Ans.
Process vs Thread differences and synchronization, deadlock examples
Process is an instance of a program while thread is a subset of a process
Processes are independent while threads share the same memory space
Synchronization is used to coordinate access to shared resources
Deadlock occurs when two or more threads are blocked waiting for each other to release resources
Examples of synchronization include mutex, semaphore, ...
- Q8. Database: Design with one-one mapping, one-many mapping…some basic questions, I don’t remember all
- Q9. Design a website where after user request. A bunch of processes need to be executed and then a mail is sent to user with the result. Take care of scalability etc?
- Ans.
Design a scalable website to process user requests and send email results asynchronously.
Use a microservices architecture to handle different processes independently.
Implement a message queue (e.g., RabbitMQ, Kafka) to manage requests and responses.
Utilize cloud services (e.g., AWS Lambda) for scalable processing of tasks.
Send emails using a reliable service (e.g., SendGrid, Amazon SES) to ensure delivery.
Implement loa...
- Q10. CTO round
Interview Preparation Tips
Experience: This was CTO round, if you make this round…you are doing pretty good.
He asked a lot on what I worked on and asked questions relevant to that. Process thread, stacks heaps. A minor system design on component in their system. How they are shared between and trade-off. We discussed about scalability and challenge.
General Tips: Process:5 technical ( 3 rounds+ SVP round + CTO round ) + 1 HR
I got almost the same package that I am currently getting (Myntra gave stock options, which I don’t have in my current company) but I am looking for a change so accepted the offer.
Skills: Algorithm, data structure, database
College Name: na
Skills evaluated in this interview
I appeared for an interview before Dec 2020.
(2 Questions)
Round duration - 120 minutes
Round difficulty - Medium
The Entire Test is held in HackerRank Platform. It has:
2 coding questions (one easy and one medium)
2 output questions(medium)
2 Aptitude(easy)
1 general Computer science(medium)
It took me 30 min for each coding questions. I did not know that general question is related to bash commands.
Tips: Practice the Warmup questions in Hacker Rank.
Do some Basic aptitude questions.
Thorough with the basic C and C++ concepts
- Q1.
Binary Tree to Doubly Linked List
Transform a given Binary Tree into a Doubly Linked List.
Ensure that the nodes in the Doubly Linked List follow the Inorder Traversal of the Binary Tree.
Input:
The fi... - Ans.
Convert a Binary Tree into a Doubly Linked List following Inorder Traversal.
Perform Inorder Traversal of the Binary Tree to get the nodes in order.
Create a Doubly Linked List by linking the nodes in the order obtained from Inorder Traversal.
Return the head of the Doubly Linked List as the output.
- Q2.
Unique Element in Array
Given an arbitrary array
arrconsisting ofNnon-negative integers where every element appears thrice except for one. Your task is to find the element in the array that appears onl... - Ans.
Find the unique element in an array where every other element appears thrice.
Use XOR operation to find the unique element.
Iterate through the array and XOR each element to find the unique one.
Return the unique element as the answer.
(2 Questions)
Round duration - 60 minutes
Round difficulty - Medium
It's completely around the data structures. The questions are a bit tricky but once u think without any tension u can get through easily. The interviewer is helpful and gives u few hints if u catch them at the right point of time u got it.
Tips: got through Data Structures and Algorithms Made Easy by Narasimha Karumanchi. It's a best book for the interviews.
- Q1.
Binary Tree Traversals Problem Statement
Given a Binary Tree with 'N' nodes, where each node holds an integer value, your task is to compute the In-Order, Pre-Order, and Post-Order traversals of the binar...
- Ans.
Implement a function to compute In-Order, Pre-Order, and Post-Order traversals of a Binary Tree given in level-order format.
Parse the input level-order tree elements to construct the binary tree.
Implement recursive functions for In-Order, Pre-Order, and Post-Order traversals.
Return the traversals as lists of lists for each test case.
- Q2.
Delete N Nodes After M Nodes in a Linked List
Given a singly linked list and two integers 'N' and 'M', traverse the linked list to retain 'M' nodes and then delete the next 'N' nodes. Continue this proces...
- Ans.
Traverse a linked list to retain 'M' nodes and then delete the next 'N' nodes, repeating until the end of the list.
Create a function that takes the head of the linked list, 'N', and 'M' as input parameters.
Traverse the linked list, retaining 'M' nodes and deleting the next 'N' nodes in each iteration.
Update the pointers accordingly to skip 'N' nodes after retaining 'M' nodes.
Repeat this process until the end of the lin...
(1 Question)
Round duration - 60 minutes
Round difficulty - Easy
The interviewer asked to put everything on the blackboard and write down the code of each and everything.
Question : Explain all the search algorithm you know with space and Time complexities.
Answer : Linear search : It is a sequential search algorithm where the entire array is traversed till the desired element is not found. Time complexity is O(N) and auxiliary space is O(1).
Binary search : In this algorithm, a sorted array is searched by repeatedly dividing the search interval in half.
Steps :
1. Initially the interval covers the whole array.
2. If the value to be searched is less than the item in the middle of the interval, narrow the interval to the lower half. Otherwise, narrow it to the upper half.
3. The process is repeated until the value is found or the interval is empty.
Time complexity is O(log n) and auxiliary space is O(1) in case of iterative implementation.
- Q1.
Maximum Frequency Number Problem Statement
Given an array of integers with numbers in random order, write a program to find and return the number which appears the most frequently in the array.
If multip...
- Ans.
Program to find the number with maximum frequency in an array of integers.
Create a dictionary to store the frequency of each number in the array.
Iterate through the array and update the frequency count in the dictionary.
Find the number with the maximum frequency in the dictionary and return it.
If multiple elements have the same maximum frequency, return the one with the lowest index.
Interview Preparation Tips
Tip 1 : Must do Previously asked Interview as well as Online Test Questions.
Tip 2 : Go through all the previous interview experiences from Codestudio and Leetcode.
Tip 3 : Do at-least 2 good projects and you must know every bit of them.
Tip 1 : Have at-least 2 good projects explained in short with all important points covered.
Tip 2 : Every skill must be mentioned.
Tip 3 : Focus on skills, projects and experiences more.
Skills evaluated in this interview
I appeared for an interview before Dec 2020.
(2 Questions)
Round duration - 120 minutes
Round difficulty - Medium
This was a 2 hour round consisting of 5 mcqs and 2 codes. The mcqs were pretty much simple based on DS, DBMS, OS, OOP, and C.
- Q1.
Rabbit Jumping Problem
Consider 'n' carrots numbered from 1 to 'n' and 'k' rabbits. Each rabbit jumps to carrots only at multiples of its respective jumping factor Aj (i.e., Aj, 2Aj, 3Aj, ...), for all ra...
- Ans.
Calculate uneaten carrots by rabbits with specific jumping factors.
Iterate through each carrot and check if any rabbit jumps on it.
Use the jumping factors to determine which carrots are eaten.
Subtract the eaten carrots from the total to get the uneaten count.
- Q2.
Flip Bits Problem Explanation
Given an array of integers
ARRof size N, consisting of 0s and 1s, you need to select a sub-array and flip its bits. Your task is to return the maximum count of 1s that can b... - Ans.
Given an array of 0s and 1s, find the maximum count of 1s by flipping a sub-array at most once.
Iterate through the array and keep track of the maximum count of 1s obtained by flipping a sub-array.
Consider flipping a sub-array from index i to j by changing 0s to 1s and vice versa.
Update the maximum count of 1s if the current count after flipping is greater.
Return the maximum count of 1s obtained by flipping a sub-array ...
(2 Questions)
Round duration - 60 minutes
Round difficulty - Medium
Started with a brief discussion on my projects and internships. A thorough discussion on whichever languages, frameworks I had used in my projects. Followed by discussion on coding questions. Apart from the codes there were some questions on OS, process stack, heap memory in Java, Garbage collection, OOP principles and comparison based sorting
- Q1.
Sum of Maximum and Minimum Elements Problem Statement
Given an array
ARRof sizeN, your objective is to determine the sum of the largest and smallest elements within the array.Follow Up:
Can you achie...
- Ans.
Find sum of maximum and minimum elements in an array with least number of comparisons.
Iterate through the array and compare each element with current maximum and minimum to update them.
Initialize max as smallest possible value and min as largest possible value.
Return the sum of max and min after iterating through the array.
- Q2.
Invert a Binary Tree Problem Statement
Given a Binary Tree and one of its leaf nodes, invert the binary tree by following these guidelines:
• The given leaf node becomes the root after the inversion. • F...
- Ans.
Invert a binary tree based on a given leaf node as the root.
Start by finding the leaf node in the binary tree.
Move the left child of the leaf node to the right side of the leaf node.
Make the parent of the leaf node the left child of the leaf node.
Repeat the process for each test case.
Return the inverted binary tree in level order format.
(3 Questions)
Round duration - 60 minutes
Round difficulty - Medium
Questions based on programming, DBMS and puzzles were asked in this round.
- Q1.
Rearrange Array to Form Largest Number
Given an array
ARRconsisting of non-negative integers, rearrange the numbers to form the largest possible number. The digits within each number cannot be changed....
- Ans.
Rearrange the array elements to form the largest possible number by concatenating them.
Sort the array elements in a custom way where the concatenation of two numbers results in a larger number.
Use a custom comparator function while sorting the array elements.
Convert the sorted array elements to a single string to get the largest possible number.
- Q2. What is indexing in the context of databases?
- Ans.
Indexing in databases is a technique used to improve the speed of data retrieval by creating a data structure that allows for quick lookups.
Indexes are created on columns in a database table to speed up the retrieval of rows that match a certain condition.
They work similar to the index in a book, allowing the database to quickly find the relevant data without having to scan the entire table.
Examples of indexes include ...
- Q3. What are the advantages of B+ Trees in database management systems?
- Ans.
B+ Trees are advantageous in database management systems due to their ability to efficiently store and retrieve data.
B+ Trees have a high fanout, allowing for more keys to be stored in each node, reducing the height of the tree and improving search performance.
B+ Trees are balanced trees, ensuring that operations like search, insertion, and deletion have a predictable time complexity of O(log n).
B+ Trees are optimized ...
Round duration - 45 minutes
Round difficulty - Medium
Puzzles and HR based questions were asked in this round.
He asked questions like : what are my career goals, what do you look forward to in a boss , how do you see yourself in 5 years ,etc etc .
Interview Preparation Tips
Tip 1 : Must do Previously asked Interview as well as Online Test Questions.
Tip 2 : Go through all the previous interview experiences from Codestudio and Leetcode.
Tip 3 : Do at-least 2 good projects and you must know every bit of them.
Tip 1 : Have at-least 2 good projects explained in short with all important points covered.
Tip 2 : Every skill must be mentioned.
Tip 3 : Focus on skills, projects and experiences more
Skills evaluated in this interview
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