American Express Technology Interview Experience (On-Campus)

American Express visits my university campus every year to hire interns for technology roles. I would like to share my experience during the selection process for a summer internship as a Technology Intern at American Express.

The selection process consisted of an Online Assessment followed by two rounds of interviews, one of which was technical and the other was a mix of technical and HR.

Round 1: Online Assessment (Coding Test)
Duration: 1 hour 30 minutes

There was no negative marking for incorrect answers. The problems covered graph algorithms, binary search, and an easy problem that I managed to solve using a brute-force approach. While my solutions weren’t highly optimized, they produced correct outputs for the visible test cases provided in the Amex Test. It’s worth noting that not all test cases were shown, as some were hidden.

Tips:

• Aim to solve questions quickly to increase your chances of advancing to the interview rounds.
• Ensure a thorough understanding of the problem statement. If you’re struggling with a problem, consider moving on to others before spending too much time on one.

Preparation:

After the coding round, six students, including me, were shortlisted for the interview stage. We had a day to prepare for it. My preparation was divided into four main areas:

• Data Structures and Algorithms: I had previously solved 150 top interview questions and completed LeetCode 75 problems. I revisited these and reviewed quick problem-solving approaches.
• Computer Science Fundamentals: I refreshed my knowledge of Database Management Systems (DBMS) using the top interview questions from JavaTpoint. I also revisited Object-Oriented Programming (OOPS) concepts from the top interview questions on Interviewbit.
• Puzzles: I tackled around 50–60 puzzles from GeeksforGeeks to enhance my problem-solving skills.
• Projects: I ensured a deep understanding of my projects, including implementation details and the reasons behind the chosen tech stack. Comprehensive knowledge of projects provides an advantage during interviews.

Round 2: Technical Interview
Duration: 45 minutes

The technical interview began with a brief self-introduction and then delved into a mix of questions spanning DSA, DBMS, and OOPS.

• The interviewer started with a basic question: finding the minimum element in an array.
• I was then asked to determine the 49th smallest element in an array in an optimized way. Additionally, I had to explain the impact on the result if the array size was 15.
• The classic problem of finding the Kth largest element in an array followed. I began with a brute-force approach and later optimized it using priority queues.
• The interviewer explored my knowledge of linked lists, including the complexities related to them.
• I explained the differences between Merge Sort and Quick Sort and when Quick Sort’s time complexity becomes O(n²).
• A tricky question emerged: deleting a node from a linked list when given the node’s address directly.
• The conversation shifted to DBMS, where I discussed normalization extensively. I also explained denormalization and its purpose.
• I was asked to write SQL queries for various scenarios.
• The interview concluded with some basic OOPS questions.
• The interviewer emphasized time complexities and optimization approaches for each problem.

Shortly after completing the interview, I received a call for the second-round interview, which involved project discussion, HR, and additional technical questions. Only four out of the six students moved on to this stage.

Round 3: Technical + HR Interview + Project Discussion
Duration: Approximately 40 minutes

This interview began with a brief introduction. As I mentioned DESIS Ascend Educare Scholar (mentee of D.E.Shaw & Co.) in my resume, I was asked about my experiences and lessons learned during that time.

Next, we discussed my projects in detail, focusing on workflow and tech stack choices. I was also questioned about my understanding of American Express and how I could contribute to the organization.

The interviewer presented real-world scenarios for problem-solving. One such scenario involved designing a library management system’s UI/UX, detailing components and buttons in the navigation bar. I explained the system’s conditions, including login/signup procedures for students and administrators. Additionally, I addressed the implications of simultaneous orders of the same product.

This interview focused almost on my resume and project experiences.

Verdict: SELECTED

Tips for Interviews:

• Prioritize strengthening your DSA skills by practicing daily, aiming for at least 3 to 4 problems.
• Thoroughly prepare core subjects like DBMS, OOPS, OS, and networking.
• Develop at least one significant project to discuss during interviews.
• Ask relevant questions to interviewers when given the chance.
• Be honest on your resume; avoid including items you haven’t done or don’t recall confidently.
• Approach your preparation with dedication and authenticity.

Best of luck with your interview preparation!