# Software Engineer II
**Role:** Software Engineer · **Level:** IC14
**Company:** [Pinterest](https://scaleengineer.com/companies/pinterest)
**Difficulty:** Medium to Hard
**Salary:** US$130000 - US$170000
**Experience:** 3 - 6
**Timeline:** ~7 days
This interview process is for a Software Engineer II (IC14) position at Pinterest. It is designed to assess a candidate's technical skills, problem-solving abilities, system design knowledge, and cultural fit within the company.
Canonical: https://scaleengineer.com/interviews/pinterest/ic14-software-engineer
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## Overall evaluation

- Technical Skills
- System Design
- Behavioral and Cultural Fit

## Questions asked

- Given a stream of data, how would you find the k most frequent elements?
- Design a rate limiter for an API.
- Tell me about a time you disagreed with a technical decision and how you handled it.
- How would you design a system to detect duplicate pins?
- Explain the difference between a process and a thread.
- What are the trade-offs of using microservices vs. a monolith?
- Describe a situation where you had to mentor a junior engineer.
- How would you implement a cache for frequently accessed data?
- Write a function to find the lowest common ancestor of two nodes in a binary tree.
- How do you ensure the quality of your code?

## Preparation tips

### lists

- Review fundamental data structures (arrays, linked lists, trees, graphs, hash tables) and algorithms (sorting, searching, dynamic programming, graph traversal).
- Practice coding problems on platforms like LeetCode, HackerRank, focusing on medium to hard difficulty.
- Study system design concepts: scalability, availability, consistency, databases (SQL/NoSQL), caching, load balancing, message queues.
- Prepare for behavioral questions using the STAR method (Situation, Task, Action, Result). Think about your past projects and experiences.
- Understand Pinterest's products and business to better contextualize system design and behavioral questions.
- Practice explaining your thought process clearly and concisely.
- Mock interviews can be very helpful to simulate the interview environment.

### studyPlan

- {"title":"Foundational Data Structures and Algorithms","longDescription":"Weeks 1-2: Focus on core data structures (Arrays, Linked Lists, Stacks, Queues, Trees, Graphs, Hash Tables) and their common operations. Practice basic algorithms like sorting (Merge Sort, Quick Sort) and searching (Binary Search).","shortDescription":"Weeks 1-2: Data Structures & Basic Algorithms."}
- {"title":"Advanced Algorithms and Problem Solving","longDescription":"Weeks 3-4: Dive into more advanced algorithms such as Dynamic Programming, Graph Algorithms (BFS, DFS, Dijkstra's), and String Manipulation. Start practicing medium-difficulty coding problems.","shortDescription":"Weeks 3-4: Advanced Algorithms & Medium Coding Problems."}
- {"title":"System Design","longDescription":"Weeks 5-6: Concentrate on System Design. Study concepts like scalability, load balancing, caching, databases (SQL vs. NoSQL), and message queues. Practice designing common systems (e.g., Twitter feed, URL shortener).","shortDescription":"Weeks 5-6: System Design Fundamentals."}
- {"title":"Behavioral and Cultural Fit","longDescription":"Week 7: Focus on Behavioral preparation. Use the STAR method to prepare stories for common behavioral questions related to teamwork, problem-solving, leadership, and dealing with challenges. Review Pinterest's values and mission.","shortDescription":"Week 7: Behavioral Preparation & Company Values."}

## Location differences

- {"location":"San Francisco Bay Area","differences":{"tips":["For SF/Bay Area: Be prepared for highly competitive technical questions and a strong emphasis on impact and ownership.","For Seattle: Expect a focus on collaborative problem-solving and clear communication of technical concepts.","For New York: Behavioral questions might delve deeper into adaptability and handling ambiguity in a fast-paced environment."],"interviewFocus":["Emphasis on practical application of data structures and algorithms relevant to Pinterest's scale.","Behavioral questions often probe for collaboration and impact within a team.","System design questions may lean towards real-time data processing and recommendation systems."],"commonQuestions":["How would you design a URL shortener for Pinterest?","Discuss a time you had to deal with a difficult stakeholder.","Explain the trade-offs between SQL and NoSQL databases for a specific Pinterest feature."]}}
- {"location":"Seattle","differences":{"tips":["For Seattle: Highlight your experience with large-scale systems and distributed computing.","Be ready to whiteboard complex algorithms and data structures.","Demonstrate a clear thought process and ability to articulate trade-offs."],"interviewFocus":["Strong focus on data structures and algorithms, with a preference for efficient solutions.","System design questions often revolve around scalability and fault tolerance.","Behavioral questions assess problem-solving approach and learning from failures."],"commonQuestions":["Design a system to handle real-time notifications for new pins.","Describe a challenging bug you encountered and how you debugged it.","How would you optimize a query for a large dataset of user preferences?"]}}

## Round 1: Coding and Algorithms
**Type:** Technical Interview (Coding) · **Difficulty:** Medium · **Duration:** 45 min
Coding challenge focused on data structures and algorithms.
This round focuses on your core programming skills. You will be asked to solve one or two coding problems, typically involving data structures and algorithms. The interviewer will assess your ability to write clean, efficient, and correct code, as well as your problem-solving approach and communication skills.
**Interviewers look for:** A candidate who can translate a problem into efficient, working code.; Clear articulation of the problem-solving process.; Understanding of time and space complexity.; Ability to debug and refine code.
**Evaluation criteria:** Correctness of the solution; Efficiency of the solution (time and space complexity); Code readability and maintainability; Ability to handle edge cases; Communication of approach
**Common rejection reasons:** Inability to write clean, working code.; Poor understanding of fundamental data structures and algorithms.; Difficulty explaining thought process.; Not addressing edge cases.
## Questions

- Given an array of integers, find the contiguous subarray with the largest sum.
- Implement a function to reverse a linked list.

## Preparation tips

- Practice coding on a whiteboard or a shared editor.
- Think out loud and explain your approach before coding.
- Consider different approaches and discuss their trade-offs.
- Test your code with various inputs, including edge cases.

## Round 2: System Design
**Type:** System Design Interview · **Difficulty:** Hard · **Duration:** 60 min
Design a scalable system or feature.
In this round, you'll be asked to design a system or a feature, often related to Pinterest's products. This could involve designing a news feed, a recommendation engine, or a notification system. The focus is on your ability to think about scalability, reliability, performance, and trade-offs in a distributed environment.
**Interviewers look for:** A candidate who can design scalable, reliable, and maintainable systems.; Understanding of distributed systems concepts.; Ability to break down complex problems into manageable components.; Pragmatic approach to design choices.
**Evaluation criteria:** Clarity and completeness of the design; Scalability and performance; Robustness and fault tolerance; Choice of technologies and justification; Ability to discuss trade-offs
**Common rejection reasons:** Lack of understanding of system design principles.; Inability to handle scale and performance considerations.; Poor trade-off analysis.; Not considering failure scenarios.
## Questions

- Design a system to show related pins on a pin's page.
- Design a distributed cache system.

## Preparation tips

- Study common system design patterns and architectures.
- Practice designing systems for scale.
- Be prepared to discuss databases, caching strategies, load balancing, and APIs.
- Clearly articulate your design choices and the reasoning behind them.

## Round 3: Behavioral and Cultural Fit
**Type:** Behavioral Interview · **Difficulty:** Medium · **Duration:** 45 min
Assesses past behavior and cultural fit.
This interview assesses your behavioral competencies and how you align with Pinterest's culture and values. You'll be asked questions about your past experiences, focusing on how you've handled specific situations related to teamwork, challenges, successes, and failures. The STAR method (Situation, Task, Action, Result) is highly recommended for answering these questions.
**Interviewers look for:** A candidate who is a good cultural fit for Pinterest.; Evidence of collaboration, ownership, and impact.; Ability to learn and adapt.; Positive attitude and enthusiasm.
**Evaluation criteria:** Communication clarity; Examples of past behavior; Problem-solving approach; Teamwork and collaboration; Cultural alignment
**Common rejection reasons:** Poor communication skills.; Lack of collaboration or teamwork.; Inability to provide specific examples.; Not demonstrating alignment with company values.; Negative attitude.
## Questions

- Tell me about a time you faced a significant technical challenge and how you overcame it.
- Describe a situation where you had to work with a difficult team member.

## Preparation tips

- Prepare specific examples using the STAR method.
- Research Pinterest's mission, values, and culture.
- Be honest and authentic in your responses.
- Show enthusiasm for the role and the company.