Pinterest Software Engineer Interview

In the Recruiter Call round of the Pinterest Software Engineer interview process, you'll speak directly with a recruiter from Pinterest. They'll provide you with more details about the role you're applying for, including your responsibilities, company culture, and upcoming rounds. The recruiter might also ask you some questions to understand your skills and experience better.

Feel free to ask any questions you have; remember, this is a chance for both you and Pinterest to see if you're a good fit for each other.

• Can you tell me about your experience as a software engineer?
• What interests you about this role at Pinterest?
• Have you worked on any projects related to [specific technology or skill mentioned in the job description]?
• How do you approach problem-solving in your work?
• Can you walk me through a challenging project you've completed in the past?
• Are you open to relocating or working remotely?
• Do you have any questions about the role or the company?

In this round, you'll have a 45 to 60-minute discussion with a Pinterest engineer or a Karat.io interviewer. 

Typically, 

• The session starts with a brief introduction where interviewers introduce themselves and proceed to ask you a few questions about your professional journey
• Then, you'll be presented with one or two coding questions, often centred around data structures and algorithms. To facilitate this coding portion, you may use collaborative coding tools like CoderPad or JSFiddle. Depending on the role, there may also be elements of domain-specific knowledge included in the questions.
• Finally, after the coding portion, you'll have around five minutes to ask any additional questions you may have about the role or Pinterest as a company.

The purpose of the phone screening is to evaluate your general programming skills, (and any specialised knowledge relevant to the role), all while providing you with an opportunity to learn more about the position and Pinterest.

During the onsite interview, you’ll visit the Pinterest office for (typically) five interview sessions, covering the following interview formats:

• Technical Interview — (Data Structures/Algorithms)
• Architecture/Systems Design Interview
• Domain Interview
• Lunch Interview / Managerial Interview with HR / Culture Fit or Values Discussion

Technical Interview

In this round, you'll tackle a programming problem that mirrors real-life situations, using common tools like data structures and algorithms. The best part is you can use the programming language you're most comfortable with.

The question usually has multiple ways to solve it, ranging from simpler methods to more advanced ones. For example, you could be asked to write a function that checks if a given string is a palindrome or not. So, you might start with a naive approach that involves iterating through the string to compare characters, and then optimise it by using techniques like two-pointer traversal or employing a stack data structure.

If time allows, your interviewers might want to explore additional questions. They will inquire about your thought process, how you approach problem-solving, and how you analyse trade-offs between different solutions. The aim here is to see how you approach practical programming challenges that you might encounter in your everyday work.

Don't worry about facing overly complicated techniques like dynamic programming; those are typically not part of SDE interviews at Pinterest.

Architecture/Systems Design Interview

In this interview, you'll encounter an open-ended problem to design a large-scale system. Your task is to come up with a comprehensive technical solution to address the problem. 

Here's 3 things to know:

• The problem presented will cover a broad range of technical challenges. This includes outlining the architecture of the system, discussing data storage and retrieval mechanisms, defining communication protocols between different components, and considering scalability and performance aspects. For instance, “Design an efficient API for a social media platform. How will you handle computation tasks both online and offline? How will you make decisions about client-server communication and data storage?”
• Depending on the role you're applying for, the problem may have domain-specific aspects. For example, if you're interviewing for a position related to e-commerce, you may be asked questions like “Design a system for managing product catalogues and processing orders efficiently.”
• While you won't typically write code during these interviews, you may be asked to create architecture diagrams or otherwise present your solution visually. You should also be ready to answer questions and discuss your approach in detail.

We'd recommend practising this interview with a mock interviewer. There are several software engineers who provide great practice and guidance on dealing with the twists and turns this interview can take — and you can book a slot with them on Prepfully.

Domain-Specific

In this interview, they will be looking to assess your expertise in a specific area/domain. For instance, if you're applying for an iOS developer role, you might be asked about your experience with building iOS applications, frameworks like UIKit or SwiftUI, and so on. For a machine learning role, they will focus on libraries like TensorFlow or PyTorch.

Depending on the domain, you will also need to demonstrate proficiency in specific programming languages. For example, if you're interviewing for an iOS role, you might be asked about Objective-C or Swift, while for an Android role, it could be Java or Kotli. Similarly, a data processing role will demand familiarity with Python or SQL.

Lunch Interview / Managerial Interview with HR / Culture Fit or Values Discussion

In this round, you'll talk with a hiring manager or someone from HR about your work experience and how it fits with the job. They might ask about your achievements, challenges you've faced, and how you work with others. They'll want to know if you'd fit in well with the company and its goals. You can also ask questions about Pinterest's culture and what it's like to work there.

Sometimes, this interview happens during lunch. Therefore, it's more relaxed and gives you a chance to chat about things outside of work, like hobbies and interests.

• What is the time complexity of reversing a Binary Tree?
• How would you create an autocomplete feature that suggests the top n options based on a search query and a list of stored word/phrase suggestions, each with a score? Additionally, how would you optimise this solution for memory and performance as the input scales up?
• Can you build a to-do list using React?
• Given the availability of multiple users, how would you find common time slots when they are all available?
• Share an experience when you had difficulty getting along with a coworker.
• How would you serialise and deserialize a binary tree to/from a string?
• What do you know about Pinterest?
• Sort an array containing only 0s, 1s, and 2s.
• Explain the difference between UIKit and SwiftUI.
• How would you go about developing a recommendation system for an e-commerce platform?
• Define overfitting and discuss strategies for preventing it.
• Describe the difference between client-side and server-side rendering.
• Walk me through the process of cleaning and preprocessing a dataset for analysis. How would you handle missing values in a dataset?