Airbnb Software Engineer Interview Guide

It's an online test that candidates have to get through to qualify for the interview rounds. There will be 3 coding questions to be answered within 120 minutes. The difficulty level of the questions is generally medium.

Sample question:

A milkman supplies milk in packaged bottles of varied sizes. The possible sizes of the bottles are {1, 5, 7 and 10} litres. He wants to supply the desired quantity using the minimum no. of bottles irrespective of the size. Your task is to help him find the minimum number of bottles required to supply the given demand for milk.

Input Format:

The first line contains the number of test cases N

Next "N" lines, each contains a positive integer Li which corresponds to the demand for milk.

Output Format:

For each input Li, print the minimum number of bottles required to fulfil the demand

Constraints:

1 <= N <= 1000 Li > 0 1 <= i <= N

For more such questions, you may want to check this out: 

On clearing the Hacker Rank test, candidates will get a call for the recruiter screen, which is a 45-minute telephonic interview with the hiring manager. Here, the interviewer is going to assess whether your experience and skill sets are a good match for the job you’ve applied for. Most of the questions are going to be based on your previous experience/resume. Hence, you should prioritize preparing your resume well over any other thing for this round. Some questions regarding your motivation for the role and company might also be asked. So, prepare some good points for these questions beforehand, especially the expected "Why Airbnb?" or "Why a career in software engineering?"

Once you have cleared the Recruiter Screen, you will proceed to the Phone Screen. The phone screen is a telephonic interview round with an Airbnb Software engineer. This interview will last for about 1 hour. The phone Screen is designed to test your technical skills Questions in this round are going to be theoretical, conceptual, and will also involve some coding through a shared online editor.

 Here are a couple of important topics from which questions are asked in this round:

• Coding
• System Design

Most asked questions in the Phone Screen

Coding

• Suppose you are given an array of distinct integer candidates and a target integer "target", write a function to return a list of all unique combinations of candidates where the chosen numbers add up to target in these algorithms.
• Write a function to find the number of ways in which you can move N meters by doing jumps of 1, 2, 3, 4, or 5-meter lengths. Assume that N can be a very large number. 
• Write a function to find the first repeated character from a given string.

System Design

• Given x, y, z : how would you design the infrastructure for a real-world chatbot system?
• Design a cache system to store data locally and flush it after the overflow.
• Design a Banking System having different products, two of which are the savings and current account. The system should be able to add a customer, create an account and debit/credit into the account
• Design an online voting system app.

The onsite interview round for the Airbnb Software engineer role is a more in-depth version of the technical phone screen. It takes place at one of Airbnb's campuses. The interview panel consists of 4-6 interviewers who are software engineers, product managers, and HR managers at Airbnb.  The onsite round consists of 3 interviews.

The first two interviews are technical while the third and last one is a behavioural interview.

Technical Interviews

The two Technical interviews focus on testing the coding and system design abilities of the candidate. Each of these interviews is conducted an hour-long and is conducted by a senior software engineer at Airbnb.

Behavioral interview

It's the final interview of the onsite round. The behavioral interview is 1-hour long and is conducted by senior managers from Airbnb. This interview mainly aims to test a candidate's motivation for the role, leadership skills, and how good a fit they will be in the company. Questions in this interview are mostly situation-based.

• An overwhelming focus is going to be on coding. So, candidates must practice well to ace the coding round.
• Focus on scenario-based system design questions.
• Do not rush to answer, and take your time.
• Do not hesitate to ask clarifying questions.
• Follow the think-out-loud approach for answering open-ended questions.

Most asked questions in the technical interviews (Onsite Round)

Coding

• Write a code to reverse a linked list.
• Write a code to find the smallest number, greater than a given number p, which does not have '11' in its binary representation.
• Write a function to print the mirror of a binary tree.
• Write a program to concatenate the reverse of two given strings.
• Write a function to replace each element in an array with its rank.

System Design

• Design a low-level payment app such as Paytm.
• Design the back-end of a ride-sharing service app such  service such as Uber
• What do you understand about High Availability Design?

Most asked questions in the Behavioral interview:

• What Airbnb values appeal to you the most?
• Is there anything about the work culture at Airbnb that you would want to change?
• Why do you want to pursue software engineering as a career?
• How do you deal with failures?