# Software Engineer
**Role:** Software Engineer · **Level:** L4
**Company:** [Wish](https://scaleengineer.com/companies/wish)
**Difficulty:** Medium to Hard
**Salary:** US$120000 - US$160000
**Experience:** 3 - 7
**Timeline:** ~14 days
The Software Engineer L4 interview at Wish is designed to assess a candidate's technical proficiency, problem-solving abilities, and cultural fit within the company. It typically involves multiple rounds, including technical assessments, behavioral questions, and system design challenges, to ensure the candidate can contribute effectively to Wish's engineering goals.
Canonical: https://scaleengineer.com/interviews/wish/l4-software-engineer
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## Overall evaluation

- Technical Skills
- Communication Skills
- Behavioral and Cultural Fit

## Questions asked

- Given an array of integers, find the contiguous subarray with the largest sum.
- Design a system to shorten URLs.
- Tell me about a time you disagreed with a teammate. How did you handle it?
- Implement a function to reverse a linked list.
- How would you design a news feed for a social media platform?
- Describe a challenging bug you encountered and how you debugged it.
- What are the differences between SQL and NoSQL databases?
- Explain the concept of concurrency and how you would handle it in a multi-threaded application.
- How would you optimize the performance of a web application?
- Tell me about a project you are particularly proud of.

## Preparation tips

### lists

- Review fundamental data structures and algorithms (arrays, linked lists, trees, graphs, hash maps, sorting, searching).
- Practice coding problems on platforms like LeetCode, HackerRank, or Coderbyte, focusing on medium to hard difficulty.
- Study system design principles, including scalability, reliability, availability, and performance.
- Prepare for behavioral questions by using the STAR method (Situation, Task, Action, Result) to structure your answers.
- Research Wish's products, mission, and recent news to understand the company's context.
- Understand common software engineering best practices, such as SOLID principles, design patterns, and testing methodologies.
- Be prepared to discuss your past projects in detail, highlighting your contributions and the technical challenges you faced.

### studyPlan

- {"title":"Data Structures and Algorithms Fundamentals","longDescription":"Weeks 1-2: Focus on core data structures (arrays, linked lists, stacks, queues, hash maps) and basic algorithms (sorting, searching). Practice implementing these from scratch and analyze their time and space complexity. Solve 10-15 LeetCode Easy and Medium problems related to these topics.","shortDescription":"Weeks 1-2: Data Structures & Basic Algorithms. Practice LeetCode Easy/Medium."}
- {"title":"Advanced Data Structures","longDescription":"Weeks 3-4: Dive into more advanced data structures like trees (binary trees, BSTs, tries) and graphs. Cover graph traversal algorithms (BFS, DFS) and common tree algorithms. Solve 10-15 LeetCode Medium problems focusing on these structures.","shortDescription":"Weeks 3-4: Advanced Data Structures (Trees, Graphs). Practice LeetCode Medium."}
- {"title":"Algorithmic Paradigms","longDescription":"Weeks 5-6: Focus on dynamic programming, greedy algorithms, and backtracking. These are often found in harder LeetCode problems. Aim to solve 5-10 LeetCode Medium/Hard problems in these categories.","shortDescription":"Weeks 5-6: Dynamic Programming, Greedy, Backtracking. Practice LeetCode Medium/Hard."}
- {"title":"System Design Basics","longDescription":"Weeks 7-8: Begin system design preparation. Study concepts like load balancing, caching, databases (SQL vs. NoSQL), message queues, and API design. Read system design case studies and practice designing common systems (e.g., Twitter feed, URL shortener).","shortDescription":"Weeks 7-8: System Design Fundamentals. Study scalability, databases, caching."}
- {"title":"Advanced System Design","longDescription":"Weeks 9-10: Deepen system design knowledge. Focus on distributed systems concepts, consistency models, and trade-offs. Practice designing more complex systems and be ready to discuss trade-offs. Review common interview questions for system design.","shortDescription":"Weeks 9-10: Advanced System Design. Distributed systems, trade-offs. Practice complex designs."}
- {"title":"Behavioral Preparation","longDescription":"Weeks 11-12: Prepare for behavioral questions. Reflect on your past experiences and prepare STAR method answers for common questions related to teamwork, challenges, failures, and successes. Also, review Wish's company values and prepare to align your answers.","shortDescription":"Weeks 11-12: Behavioral Questions (STAR method). Research Wish values."}
- {"title":"Mock Interviews","longDescription":"Week 13: Mock interviews. Conduct mock interviews with peers or mentors, focusing on both technical and behavioral aspects. Get feedback on your coding, problem-solving approach, and communication.","shortDescription":"Week 13: Mock Interviews. Practice coding and behavioral rounds."}

## Location differences

- {"location":"San Francisco","differences":{"tips":["Research Wish's tech stack and recent engineering blog posts.","Be prepared to discuss your experience with large-scale data processing and real-time systems.","Highlight any contributions to open-source projects or significant personal projects."],"interviewFocus":["Understanding of distributed systems and scalability challenges specific to e-commerce.","Experience with cloud platforms (AWS, GCP) and their services.","Ability to articulate technical decisions and their impact on business metrics."],"commonQuestions":["How would you optimize a database query for a large e-commerce platform?","Describe a time you had to deal with a production issue. What was your approach?","Explain the trade-offs between microservices and a monolithic architecture in the context of Wish's scale."]}}
- {"location":"New York","differences":{"tips":["Familiarize yourself with common algorithms and data structures, especially those relevant to search and recommendations.","Practice explaining your thought process clearly and concisely.","Be ready to discuss your approach to debugging and problem-solving."],"interviewFocus":["Proficiency in data structures and algorithms, with an emphasis on practical application.","Experience with machine learning concepts and their implementation.","Strong communication skills and ability to collaborate effectively in a team environment."],"commonQuestions":["How would you design a recommendation engine for a platform like Wish?","Discuss your experience with A/B testing and its application in product development.","Explain how you would ensure the security and privacy of user data."]}}
- {"location":"Remote","differences":{"tips":["Review fundamental computer science concepts.","Prepare examples that showcase your problem-solving skills and technical depth.","Show enthusiasm for learning and contributing to the team."],"interviewFocus":["Strong understanding of software development principles and best practices.","Experience with backend development and API design.","Ability to adapt to new technologies and learn quickly."],"commonQuestions":["How would you approach building a scalable API for a mobile application?","Describe a challenging technical problem you solved and how you approached it.","What are your thoughts on containerization technologies like Docker and Kubernetes?"]}}

## Round 1: Coding Challenge
**Type:** Technical Interview (Coding) · **Difficulty:** Medium · **Duration:** 45 min
Assess coding skills and problem-solving abilities with data structures and algorithms.
This round focuses on assessing your fundamental coding skills and problem-solving abilities. You will be asked to solve one or two coding problems, typically involving data structures and algorithms. The interviewer will evaluate your approach to solving the problem, your ability to write clean and efficient code, and your understanding of time and space complexity.
**Interviewers look for:** Ability to translate a problem into working code.; Understanding of fundamental data structures and algorithms.; Clean and maintainable code.
**Evaluation criteria:** Correctness of the solution.; Efficiency of the solution (time and space complexity).; Code quality and readability.; Problem-solving approach.
**Common rejection reasons:** Inability to articulate thought process.; Poor coding practices (e.g., no error handling, unreadable code).; Incorrect or inefficient solutions to coding problems.
## Questions

- Given an array of integers, find the contiguous subarray with the largest sum.
- Implement a function to reverse a linked list.
- Find the kth smallest element in a sorted matrix.

## Preparation tips

- Practice coding problems on platforms like LeetCode.
- Focus on understanding the underlying data structures and algorithms.
- Write clean, well-commented code.
- Be prepared to explain your thought process and the complexity of your solution.

## Round 2: System Design
**Type:** System Design Interview · **Difficulty:** Hard · **Duration:** 60 min
Assess ability to design scalable and reliable software systems.
This round evaluates your ability to design and architect scalable, reliable, and maintainable software systems. You will be presented with a high-level problem (e.g., design a URL shortener, a social media feed) and expected to discuss various aspects of the system, including data storage, APIs, scalability, and potential bottlenecks. The focus is on your thought process and ability to make informed trade-offs.
**Interviewers look for:** Ability to design complex, scalable systems.; Knowledge of various architectural patterns and technologies.; Pragmatic approach to problem-solving.; Ability to justify design decisions.
**Evaluation criteria:** Scalability of the proposed design.; Reliability and availability considerations.; Trade-offs analysis.; Clarity and completeness of the design.; Understanding of distributed systems concepts.
**Common rejection reasons:** Lack of understanding of system design principles.; Inability to handle scale and trade-offs.; Poor communication of design choices.
## Questions

- Design a system to shorten URLs.
- How would you design a news feed for a social media platform?
- Design a rate limiter.

## Preparation tips

- Study system design concepts (scalability, availability, databases, caching, load balancing).
- Practice designing common systems.
- Be prepared to discuss trade-offs between different approaches.
- Understand distributed systems principles.

## Round 3: Behavioral and Cultural Fit
**Type:** Behavioral Interview · **Difficulty:** Medium · **Duration:** 45 min
Assess behavioral competencies, past experiences, and cultural fit.
This round focuses on your past experiences, behavioral competencies, and cultural fit. You will be asked questions about your strengths, weaknesses, how you handle conflict, your motivations, and your career aspirations. The goal is to understand how you work in a team, how you approach challenges, and whether you align with Wish's culture and values.
**Interviewers look for:** Evidence of collaboration and teamwork.; Ability to handle challenges and learn from mistakes.; Alignment with Wish's values.; Passion for technology and the company's mission.
**Evaluation criteria:** Past experiences and accomplishments.; Behavioral competencies (teamwork, leadership, problem-solving).; Cultural fit with Wish.; Motivation and career goals.
**Common rejection reasons:** Lack of self-awareness.; Inability to provide specific examples.; Poor alignment with company values.; Negative attitude or lack of enthusiasm.
## Questions

- Tell me about a time you disagreed with a teammate. How did you handle it?
- Describe a challenging bug you encountered and how you debugged it.
- Why do you want to work at Wish?

## Preparation tips

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