Facebook Interview Questions, Process, and Tips

Find k closest points to origin from a set of 2D points.

• Calculate distance of each point from origin using distance formula

• Sort the points based on distance in ascending order

• Return first k points from the sorted list

iOS manual memory management requires developers to manually allocate and deallocate memory for objects.

• Developers must manually allocate memory for objects using methods like alloc and init.

• Developers must also manually deallocate memory for objects using methods like release.

• Failure to properly manage memory can lead to memory leaks and crashes.

• ARC (Automatic Reference Counting) was introduced in iOS 5 to automate me...read more

Program to print powerset of a given set

• Create an empty list to store subsets

• Loop through all possible binary numbers from 0 to 2^n-1 where n is the length of the set

• For each binary number, convert it to binary and use the 1's as indices to select elements from the set

• Add the selected elements to the list of subsets

• Return the list of subsets

Convert Roman numerals to integer in O(n) time

• Create a dictionary to map Roman numerals to integers

• Iterate through the string from right to left

• If the current numeral is less than the previous, subtract it from the total

• Else, add it to the total

• Return the total

Given a list of numbers and symbols, provide an expression that evaluates to a target number.

• Use recursion to try all possible combinations of numbers and symbols

• Check for division by zero and negative numbers

• Return False if no expression evaluates to the target number

Solve for x in a given expression with single variable.

• Simplify the expression by applying the distributive property and combining like terms.

• Isolate the variable term on one side of the equation and the constant terms on the other side.

• Solve for x by dividing both sides of the equation by the coefficient of the variable term.

• Check the solution by substituting the value of x back into the original equation.

• In this case...read more

Given a hashmap M and an input string S, return an array of all possible mutations of S using M's substitutes.

• Iterate through each character in S and get its substitutes from M

• Use recursion to generate all possible combinations of substitutes for each character

• Time complexity: O(n^m) where n is the average number of substitutes per character and m is the length of S

• Space complexity: O(n^m) due to the number of possible...read more

Facebook implements graph search by indexing user data and using natural language processing.

• Facebook indexes user data to create a graph of connections and relationships.

• Natural language processing is used to interpret user queries and return relevant results.

• Graph search allows users to search for specific information within their network, such as 'friends who like hiking'.

Facebook chat is a real-time messaging service that allows users to communicate with each other through the Facebook website or mobile app.

• Facebook chat uses XMPP (Extensible Messaging and Presence Protocol) to enable real-time communication between users.

• Messages are sent and received through Facebook's servers, which act as intermediaries between users.

• Users can see when their friends are online and available to chat...read more

Facebook stores likes/dislikes as data points in their database.

• Likes and dislikes are stored as separate data points.

• Each like/dislike is associated with a unique ID for the post or comment.

• The data is stored in Facebook's database and can be accessed through their API.

• Likes/dislikes can also be used to personalize a user's newsfeed.

• Facebook also uses likes/dislikes to gather data for targeted advertising.

Status updates can be implemented through various methods such as push notifications, real-time updates, and periodic polling.

• Use push notifications to instantly update users on important changes.

• Implement real-time updates using websockets or server-sent events for a seamless user experience.

• Periodically poll the server for updates using AJAX or other similar technologies.

• Provide a clear and concise interface for user...read more

A timeline/newsfeed can be implemented using a combination of algorithms and data structures.

• Use a database to store user activity data

• Implement an algorithm to sort the data by time

• Use pagination to limit the number of items displayed at once

• Include options for filtering and searching

• Consider using caching to improve performance

Adding someone as a friend allows you to connect with them on the platform and see their updates.

• When you add someone as a friend, they receive a notification and can choose to accept or decline your request.

• Once they accept your request, you can see their updates and they can see yours.

• You can also message each other and tag each other in posts.

• Adding someone as a friend does not give them access to your personal info...read more

Hadoop is a distributed computing framework used for storing and processing large datasets.

• Hadoop is based on the MapReduce programming model.

• It allows for parallel processing of large datasets across multiple nodes.

• Hadoop consists of two main components: HDFS for storage and MapReduce for processing.

• It is commonly used for big data analytics, machine learning, and data warehousing.

• Examples of companies using Hadoop in

FB messages work by allowing users to send and receive text, images, videos, and other media through the Facebook platform.

• Messages can be sent to individuals or groups of people.

• Users can also send voice messages and make voice and video calls through the messaging feature.

• Messages can be archived or deleted, and users can also choose to ignore or block certain senders.

• Facebook uses end-to-end encryption to protect th...read more

FB Mail is a messaging service that allows Facebook users to send and receive messages from other users.

• FB Mail is integrated into the Facebook platform and can be accessed through the Messenger app or website.

• Users can send messages to individuals or groups, and can also attach files, photos, and videos.

• FB Mail also includes features such as message requests, message filtering, and message archiving.

• Messages can be se...read more

Function to return mutual friends given two ids and getFriends(id) function

• Call getFriends(id) for both ids to get their respective friend lists

• Iterate through both lists and compare to find mutual friends

• Return the list of mutual friends

Function to return list of friends of friends in decreasing order of mutual friends

• Use a set to store all friends of friends

• Iterate through the list of friends of the given id

• For each friend, iterate through their list of friends and count mutual friends

• Sort the set of friends of friends by decreasing number of mutual friends

Given time slots, find a specific time with maximum overlap. Prove solution.

• Create a list of all start and end times

• Sort the list in ascending order

• Iterate through the list and keep track of the number of overlaps at each time

• Return the time with the maximum number of overlaps

• Prove solution by testing with different input sizes and edge cases

Find the longest sub-array with increasing order of integers.

• Iterate through the array and keep track of the current sub-array's start and end indices.

• Update the start index whenever the current element is smaller than the previous element.

• Update the end index whenever the current element is greater than or equal to the next element.

• Calculate the length of the sub-array and compare it with the longest sub-array found s

Find the length of longest increasing subsequence and print the sequence from an array of integers.

• Use dynamic programming to solve the problem

• Create an array to store the length of longest increasing subsequence ending at each index

• Traverse the array and update the length of longest increasing subsequence for each index

• Print the sequence by backtracking from the index with the maximum length

• Time complexity: O(n^2)

• Exam...read more

Code to find a given integer in a rotated sorted array.

• Use binary search to find the pivot point where the array is rotated.

• Divide the array into two subarrays and perform binary search on the appropriate subarray.

• Handle edge cases such as the target integer not being present in the array.

Use a min-heap to keep track of the largest K numbers seen so far.

• Create a min-heap of size K.

• For each incoming integer, add it to the heap if it's larger than the smallest element in the heap.

• If the heap size exceeds K, remove the smallest element.

• At the end, the heap will contain the largest K numbers in the input.

LRU Cache is a data structure that stores the most recently used items and discards the least recently used items.

• Use a doubly linked list to keep track of the order of items in the cache

• Use a hash map to store the key-value pairs for fast access

• When an item is accessed, move it to the front of the linked list

• When the cache is full, remove the least recently used item from the back of the linked list and the hash map

I feel incredibly proud and grateful for achieving this rare feat.

• I am overjoyed and humbled by this accomplishment.

• It is a testament to my hard work and dedication.

• I am grateful for the support of my team and loved ones.

• This achievement motivates me to continue striving for excellence.

• I feel honored to be recognized for my efforts.

I received offers from Google, Amazon, and Microsoft.

• Received offers from top tech companies

• Google, Amazon, and Microsoft were among the offers

• Had multiple options to choose from

The interview process involves multiple rounds of assessments and interviews.

• Initial screening through resume and application review

• First round of interview with HR or hiring manager

• Technical assessment or skills test

• Second round of interview with team or department head

• Final interview with senior management or executives

• Reference and background checks

• Job offer and negotiation

The toughest interview was for a management position at a Fortune 500 company.

• The interviewers asked challenging behavioral questions.

• I had to provide specific examples of how I handled difficult situations.

• The interview lasted for over two hours.

• I had to complete a case study and present my findings to a panel of executives.

• The competition was fierce, with several highly qualified candidates.

• I had to demonstrate my le...read more

I followed a structured study plan and practiced with mock tests regularly.

• Created a study schedule with specific goals and deadlines

• Used online resources and textbooks to supplement my learning

• Took regular mock tests to track my progress and identify areas for improvement

• Joined study groups to discuss difficult concepts and share study materials

My communication, problem-solving, and teamwork skills helped me get this job.

• Strong communication skills helped me effectively convey my ideas and collaborate with team members.

• Problem-solving skills allowed me to identify and address challenges in the workplace.

• Teamwork skills helped me work effectively with colleagues and contribute to the success of the team.

• For example, I was able to successfully lead a team proje...read more

I consulted various online resources such as industry publications, academic journals, and company websites.

• Industry publications

• Academic journals

• Company websites

Yes, grades played a role in my selection.

• Grades were one of the criteria for selection.

• My academic performance was evaluated along with other factors.

• I had to meet a certain GPA requirement to be considered.

• For example, I had to maintain a minimum of 3.0 GPA to be eligible for the program.

Advice for students aiming for similar placement offers

• Focus on building practical skills through internships and projects

• Network with professionals in your desired field

• Stay updated with industry trends and technologies

• Prepare well for interviews and aptitude tests

• Maintain a good academic record

• Be open to learning and taking feedback

• Stay motivated and persevere through rejections