Criteo

Software Engineer

Software EngineerL2Medium

The Software Engineer L2 interview at Criteo 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 a discussion about past projects and experiences. The goal is to identify candidates who can contribute effectively to Criteo's engineering teams and uphold the company's values.

Rounds

3

Timeline

~7 days

Experience

2 - 5 yrs

Salary Range

US$100000 - US$130000

Total Duration

150 min

Overall Evaluation Criteria

Technical Skills

Problem-solving skills
Technical knowledge (data structures, algorithms, system design)
Coding proficiency
Communication skills
Teamwork and collaboration
Cultural fit and alignment with Criteo's values

Communication and Collaboration

Ability to articulate thought process
Clarity of explanations
Active listening
Constructive feedback

Experience and Motivation

Past project experience
Learning agility
Adaptability
Motivation and passion for technology

Preparation Tips

1Review fundamental computer science concepts (data structures, algorithms, complexity analysis).
2Practice coding problems on platforms like LeetCode or HackerRank, focusing on medium-difficulty problems.
3Prepare to discuss your past projects in detail, highlighting your contributions and the challenges you faced.
4Brush up on system design principles, especially those relevant to Criteo's business (e.g., ad tech, real-time bidding, large-scale data processing).
5Understand Criteo's company culture, values, and recent news.
6Prepare behavioral questions using the STAR method (Situation, Task, Action, Result).
7Think about questions you want to ask the interviewer about the role, team, and company.

Study Plan

1

Data Structures and Algorithms

Weeks 1-2: DSA fundamentals and practice (2-3 problems/day).

Weeks 1-2: Focus on Data Structures and Algorithms. Cover arrays, linked lists, trees, graphs, hash tables, heaps, sorting, searching, dynamic programming, and greedy algorithms. Practice problems related to each topic, aiming for 2-3 problems per day. Understand time and space complexity analysis.

2

System Design

Weeks 3-4: System Design principles and case studies.

Weeks 3-4: System Design and Scalability. Study concepts like load balancing, caching, database design (SQL vs. NoSQL), message queues, microservices architecture, and API design. Read case studies and practice designing scalable systems. Focus on trade-offs and justifications.

3

Behavioral and Project Experience

Week 5: Behavioral questions (STAR method) and resume project review.

Week 5: Behavioral and Project Deep Dive. Prepare to discuss your resume projects in detail. Use the STAR method to structure your answers for behavioral questions related to teamwork, problem-solving, conflict resolution, and leadership. Reflect on your career goals and motivations.

4

Mock Interviews and Refinement

Week 6: Mock interviews and final review.

Week 6: Mock Interviews and Refinement. Conduct mock interviews with peers or mentors to simulate the actual interview environment. Focus on improving communication, clarity of thought, and time management. Review any weak areas identified during practice.

Commonly Asked Questions

Write a function to find the kth largest element in an unsorted array.
Design a URL shortening service like bit.ly.
Tell me about a time you disagreed with a technical decision made by your team. What did you do?
How would you optimize a slow database query?
Explain the difference between a process and a thread.
Describe a situation where you had to mentor a junior engineer.
How do you handle production issues under pressure?
Design a system to handle real-time analytics for a website.
What are the trade-offs between monolithic and microservices architectures?
Tell me about a bug you introduced and how you fixed it.

Location-Based Differences

Paris

Interview Focus

Emphasis on practical problem-solving and debugging skills.Assessment of collaboration and communication within a team.Understanding of distributed systems and scalability principles.

Common Questions

Describe a challenging technical problem you solved at your previous company.

How do you approach debugging a complex issue?

Tell me about a time you had to work with a difficult team member.

What are your thoughts on microservices architecture?

How do you ensure the scalability of your code?

Tips

Be prepared to discuss specific examples from your past projects.
Clearly articulate your thought process when solving problems.
Showcase your ability to work effectively in a team environment.
Research Criteo's tech stack and recent projects.

New York

Interview Focus

Evaluation of adaptability and learning agility.Assessment of self-awareness and professional development.Understanding of fundamental web technologies and best practices.

Common Questions

How do you handle tight deadlines and pressure?

Describe a situation where you had to adapt to a new technology quickly.

What are your strengths and weaknesses as a software engineer?

How do you stay updated with the latest industry trends?

Explain the concept of RESTful APIs.

Tips

Provide concrete examples to support your answers.
Demonstrate a proactive approach to learning and problem-solving.
Be honest about your strengths and weaknesses, and show how you are working on them.
Highlight any experience with large-scale systems or high-traffic applications.

Process Timeline

1
Data Structures and Algorithms45m
2
System Design and Architecture60m
3
Behavioral and Cultural Fit45m

Interview Rounds

3-step process with detailed breakdown for each round

1

Data Structures and Algorithms

Coding challenges to assess DSA proficiency.

Technical Interview (Coding)Medium
45 minSoftware Engineer

This round focuses on assessing your core technical skills through coding challenges. You will be asked to solve 1-2 problems related to data structures and algorithms. The interviewer will evaluate your ability to understand the problem, devise an efficient solution, write clean code, and explain your approach. Expect questions on arrays, strings, linked lists, trees, graphs, dynamic programming, and sorting/searching algorithms.

What Interviewers Look For

Strong grasp of DSAAbility to translate requirements into codeLogical thinking and systematic approachClear communication of thought process

Evaluation Criteria

Correctness of the solution
Efficiency of the solution (time and space complexity)
Code quality and readability
Problem-solving approach
Communication of the solution

Questions Asked

Given a binary tree, find its inorder traversal.

TreeRecursionIteration

Implement a function to check if a string is a palindrome, ignoring non-alphanumeric characters and case.

StringTwo Pointers

Find the first non-repeating character in a string.

StringHash Map

Preparation Tips

1Practice coding problems on platforms like LeetCode, HackerRank, or Coderbyte.
2Focus on understanding the underlying algorithms and data structures.
3Practice explaining your thought process out loud while solving problems.
4Write clean, well-commented code.
5Be prepared to discuss time and space complexity.

Common Reasons for Rejection

Inability to solve coding problems within the given time.
Poor understanding of fundamental data structures and algorithms.
Lack of clarity in explaining the thought process.
Inability to write clean, efficient, and bug-free code.
2

System Design and Architecture

Design scalable software systems and discuss trade-offs.

System Design InterviewMedium
60 minSenior Software Engineer / Architect

This round evaluates your ability to design and architect software systems. You'll be presented with a high-level problem (e.g., design a URL shortener, a social media feed, or a rate limiter) and asked to propose a solution. The focus is on scalability, reliability, performance, and trade-offs. You should be prepared to discuss database choices, caching strategies, API design, and potential bottlenecks.

What Interviewers Look For

System thinkingKnowledge of distributed systemsAbility to design for scalePragmatic approach to problem-solving

Evaluation Criteria

Ability to design scalable and reliable systems
Understanding of system components (databases, caches, load balancers, APIs)
Trade-off analysis and justification
Handling of edge cases and failure scenarios
Clarity of design and communication

Questions Asked

Design a system to count the number of views for a given YouTube video.

System DesignScalabilityDatabases

Design a distributed cache system.

System DesignDistributed SystemsCaching

How would you design a system to detect duplicate uploads of images?

System DesignHashingScalability

Preparation Tips

1Study common system design patterns and concepts.
2Read system design case studies and blogs.
3Practice designing systems for scale.
4Be prepared to justify your design choices and discuss trade-offs.
5Consider different components like databases, caches, load balancers, message queues, and CDNs.

Common Reasons for Rejection

Lack of understanding of system design principles.
Inability to handle scale and performance considerations.
Poor trade-off analysis.
Difficulty in breaking down complex problems into manageable components.
3

Behavioral and Cultural Fit

Assess past experiences, behavioral competencies, and cultural fit.

Behavioral InterviewMedium
45 minHiring Manager / Senior Team Member

This round focuses on your past experiences, behavioral competencies, and cultural fit. You'll be asked questions about how you've handled specific situations in previous roles, such as dealing with conflict, managing challenging projects, or working in a team. The interviewer wants to understand your working style, your strengths and weaknesses, and how you align with Criteo's values. Be prepared to share specific examples using the STAR method.

What Interviewers Look For

Teamwork and collaboration skillsProblem-solving approach in real-world scenariosAdaptability and resilienceCultural alignmentPassion and drive

Evaluation Criteria

Behavioral competencies (teamwork, problem-solving, adaptability)
Communication clarity and effectiveness
Self-awareness and reflection
Alignment with Criteo's values
Motivation and passion for the role

Questions Asked

Tell me about a time you failed. What did you learn from it?

BehavioralFailureLearning

Describe a situation where you had to work with a difficult colleague. How did you handle it?

BehavioralTeamworkConflict Resolution

How do you prioritize your work when you have multiple competing deadlines?

BehavioralTime ManagementPrioritization

Preparation Tips

1Review your resume and prepare specific examples for common behavioral questions.
2Use the STAR method (Situation, Task, Action, Result) to structure your answers.
3Reflect on your strengths, weaknesses, career goals, and motivations.
4Research Criteo's company culture and values.
5Be enthusiastic and genuine in your responses.

Common Reasons for Rejection

Poor communication skills.
Lack of self-awareness.
Inability to provide specific examples.
Negative attitude or lack of enthusiasm.
Poor cultural fit.

Commonly Asked DSA Questions

Frequently asked coding questions at Criteo

View all
Two SumEASYValid ParenthesesEASYSearch in Rotated Sorted ArrayMEDIUMMerge Sorted ArrayEASYIntersection of Two ArraysEASYRansom NoteEASYRandom Pick with WeightMEDIUMFlood FillEASY