Backend Engineer • Behavioral • easy

Tell me about a time you took the initiative to learn a new technology or tool because it was necessary for a project, even though it wasn't your core expertise.

#Continuous Learning #Adaptability

Practice

Backend Engineer • Behavioral • medium

At DXC, we frequently modernize legacy monolithic applications for enterprise clients. Tell me about a time you had to refactor or migrate a legacy system. What was your approach?

#Legacy Modernization #Problem Solving

Practice

Backend Engineer • Behavioral • medium

Describe a situation where you strongly disagreed with a senior engineer or architect on a technical decision. How did you handle it?

#Conflict Resolution #Communication

Practice

Backend Engineer • Behavioral • easy

How do you ensure code quality and maintainability when working under strict deadlines in a fast-paced Agile sprint?

#Agile #Code Quality

Practice

Backend Engineer • Behavioral • medium

Tell me about a time you had to troubleshoot a critical production issue under severe pressure. Walk me through your debugging process.

#Incident Management #Pressure

Practice

Backend Engineer • Behavioral • medium

DXC engineers often work directly with non-technical enterprise clients. Describe your experience gathering technical requirements from business stakeholders.

#Client Interaction #Requirements Gathering

Practice

Backend Engineer • Behavioral • medium

How do you balance the need to deliver new features quickly for a client versus the need to address accumulating technical debt?

#Prioritization #Tech Debt

Practice

Backend Engineer • Coding • medium

Find the kth largest element in an unsorted array. Note that it is the kth largest element in the sorted order, not the kth distinct element.

#Heap #Quickselect #Arrays

Practice

Backend Engineer • Coding • easy

Given a string s, find the first non-repeating character in it and return its index. If it does not exist, return -1.

#Strings #Hash Table

Practice

Backend Engineer • Coding • medium

Design and implement a data structure for Least Recently Used (LRU) cache. It should support get and put operations in O(1) time complexity.

#Design #Hash Table #Doubly Linked List

Practice

Backend Engineer • Coding • medium

Given the root of a binary tree, return the level order traversal of its nodes' values. (i.e., from left to right, level by level).

#Trees #Breadth-First Search (BFS) #Queue

Practice

Backend Engineer • Coding • medium

Given a string s, find the length of the longest substring without repeating characters.

#Strings #Sliding Window #Hash Set

Practice

Backend Engineer • Coding • medium

Given an array of intervals where intervals[i] = [starti, endi], merge all overlapping intervals, and return an array of the non-overlapping intervals that cover all the intervals in the input.

#Arrays #Sorting

Practice

Backend Engineer • Coding • easy

Reverse a singly linked list. Provide both iterative and recursive solutions.

#Linked List #Recursion

Practice

Backend Engineer • Coding • easy

Given an array of integers nums and an integer target, return indices of the two numbers such that they add up to target. Assume exactly one solution exists.

#Arrays #Hash Table

Practice

Backend Engineer • System Design • medium

Design a URL Shortening service like Bitly. Focus on the database schema and the URL generation algorithm.

#Scalability #Database Design #Algorithms

Practice

Backend Engineer • System Design • hard

How would you design a microservices architecture for an e-commerce checkout system? How do you handle inventory reservation?

#Microservices #E-commerce #Event-Driven

Practice

Backend Engineer • System Design • hard

Explain the Saga design pattern. How would you implement distributed transactions across multiple microservices?

#Microservices #Distributed Transactions

Practice

Backend Engineer • System Design • medium

How do you implement rate limiting for a public-facing API to prevent abuse?

#API Gateway #Security #Algorithms

Practice

Backend Engineer • System Design • medium

Design a centralized logging and monitoring strategy for a distributed microservices application deployed on Kubernetes.

#Observability #DevOps #Microservices

Practice

Backend Engineer • System Design • medium

How do you handle service discovery and client-side load balancing in a Spring Boot microservices ecosystem?

#Microservices #Networking #Spring Cloud

Practice

Backend Engineer • System Design • hard

Design an event-driven notification system using Apache Kafka. How do you ensure messages are not lost and are processed exactly once?

#Event-Driven #Kafka #Asynchronous

Practice

Backend Engineer • Technical • medium

What is the difference between CompletableFuture and the standard Future interface in Java?

#Concurrency #Asynchronous Programming

Practice

Backend Engineer • Technical • hard

How does Spring Boot Auto-configuration work under the hood? Explain the role of @EnableAutoConfiguration.

#Architecture #Internals #Annotations

Practice

Backend Engineer • Technical • medium

How do you handle exceptions globally in a Spring Boot REST API?

#Exception Handling #REST APIs

Practice

Backend Engineer • Technical • medium

Explain the different propagation behaviors available in Spring's @Transactional annotation. When would you use REQUIRES_NEW?

#Transactions #Database

Practice

Backend Engineer • Technical • medium

What is the difference between a clustered and a non-clustered index in a relational database?

#Database Architecture #Performance Tuning

Practice

Backend Engineer • Technical • easy

Write a SQL query to find the second highest salary from an Employee table.

#Queries #Database

Practice

Backend Engineer • Technical • easy

What is the difference between @Controller and @RestController in Spring Boot?

#Spring MVC #REST APIs

Practice

Backend Engineer • Technical • hard

How does Garbage Collection work in Java? Can you explain the difference between the G1 Garbage Collector and the CMS Collector?

#JVM #Memory Management

Practice

Backend Engineer • Technical • medium

Explain the internal working of a ConcurrentHashMap in Java 8+. How does it differ from a synchronized HashMap?

#Concurrency #Data Structures #Internals

Practice

Backend Engineer • Technical • easy

Explain the concept of Dependency Injection (DI) and Inversion of Control (IoC). What are the benefits in an enterprise application?

#Design Patterns #Spring Core

Practice

Backend Engineer • Technical • medium

How do you secure a REST API? Explain how JWT (JSON Web Tokens) work in a stateless authentication mechanism.

#Authentication #JWT #Spring Security

Practice

Backend Engineer • Technical • medium

Explain the CAP theorem. How does it apply to a NoSQL database like Cassandra versus a relational database like PostgreSQL?

#Architecture #Database

Practice

Backend Engineer • Technical • medium

What is the N+1 select problem in Hibernate/JPA? How do you resolve it?

#ORM #Performance #SQL

Practice

Cloud Engineer • Behavioral • medium

Describe a situation where you had to handle a Sev-1 production outage. What was your role, and how did you communicate with stakeholders during the incident?

#Incident Response #Communication #Under Pressure

Practice

Cloud Engineer • Behavioral • medium

Tell me about a time you experienced scope creep on a cloud migration or infrastructure project. How did you manage it while keeping the client satisfied?

#Scope Creep #Client Management #Agile

Practice

Cloud Engineer • Behavioral • medium

Tell me about a time you had a technical disagreement with a senior engineer or architect on your team regarding a cloud design. How did you resolve it?

#Conflict Resolution #Teamwork #Technical Disagreement

Practice

Cloud Engineer • Behavioral • medium

How do you explain complex cloud concepts, like containerization or serverless computing, to non-technical business stakeholders to justify project costs?

#Stakeholder Management #Communication #Business Value

Practice

Cloud Engineer • Behavioral • medium

Tell me about a time you had to push back on a client's architectural request because it violated cloud best practices or security standards.

#Communication #Pushback #Consulting #Best Practices

Practice

Cloud Engineer • Coding • medium

Write a Bash or Python script that integrates with the AWS CLI to find all IAM users who have not rotated their access keys in the last 90 days and outputs the list to a CSV.

#Python #Bash #AWS CLI #IAM #Security

Practice

Cloud Engineer • Coding • medium

Write a Python script using Boto3 (or equivalent Azure SDK) to find and delete all unattached EBS volumes older than 30 days to optimize cloud costs.

#Python #Boto3 #FinOps #Automation

Practice

Cloud Engineer • Coding • hard

Write a Terraform module to provision a secure VPC baseline, including public/private subnets across two availability zones, a NAT Gateway, and appropriate Route Tables.

#Terraform #AWS VPC #Networking #Modules

Practice

Cloud Engineer • Coding • easy

Write a bash or Python script to parse an Nginx or ALB access log file and output the top 10 IP addresses making requests.

#Bash #Python #Log Parsing #Linux

Practice

Cloud Engineer • System Design • hard

Design a CI/CD pipeline for a containerized microservices application using GitLab CI or Jenkins, deploying to a Kubernetes cluster across Dev, QA, and Prod environments.

#CI/CD #Kubernetes #Jenkins #GitLab #Deployment Strategies

Practice

Cloud Engineer • System Design • hard

Design a Disaster Recovery (DR) strategy for a mission-critical financial application with a Recovery Point Objective (RPO) of 5 minutes and a Recovery Time Objective (RTO) of 1 hour.

#Disaster Recovery #RPO/RTO #High Availability #Multi-Region

Practice

Cloud Engineer • System Design • hard

A DXC enterprise client wants to migrate a legacy on-premise monolithic application to the cloud. Walk me through your migration strategy, from assessment to cutover.

#Migration Strategies #The 6 Rs #Enterprise Architecture #Discovery

Practice

Cloud Engineer • System Design • hard

Design a highly available hybrid cloud architecture connecting a client's on-premise data center to Azure, ensuring secure and low-latency data transfer.

#Hybrid Cloud #Azure ExpressRoute #VPN Gateway #Networking

Practice

Cloud Engineer • System Design • hard

How would you implement a Zero Trust architecture in a cloud environment for a highly regulated client?

#Zero Trust #IAM #Micro-segmentation #Compliance

Practice

Cloud Engineer • System Design • hard

Design a centralized logging and monitoring solution for a multi-cloud environment (AWS and Azure) that allows developers to trace requests across microservices.

#Observability #ELK Stack #Distributed Tracing #Multi-Cloud

Practice

Cloud Engineer • System Design • medium

Design an event-driven architecture using AWS Lambda, SQS, and SNS (or Azure equivalents) to process thousands of uploaded images asynchronously.

#Event-Driven Architecture #Serverless #Microservices #Decoupling

Practice

Cloud Engineer • Technical • medium

How do you protect a public-facing cloud application from Layer 7 DDoS attacks and SQL injection?

#WAF #DDoS #Cloud Security #OWASP

Practice

Cloud Engineer • Technical • hard

What is your strategy for upgrading a production Azure Kubernetes Service (AKS) or Amazon EKS cluster with minimal downtime?

#Kubernetes #Cluster Upgrades #EKS #AKS #Zero Downtime

Practice

Cloud Engineer • Technical • hard

A client's web application hosted on EC2 instances behind an Auto Scaling Group (ASG) is experiencing intermittent high latency. How do you troubleshoot this?

#AWS #EC2 #Auto Scaling #Performance Tuning

Practice

Cloud Engineer • Technical • medium

A client's AWS bill has spiked by 40% over the last quarter. As a Cloud Engineer, what steps would you take to identify the waste and optimize their costs?

#Cost Optimization #AWS Cost Explorer #FinOps #Rightsizing

Practice

Cloud Engineer • Technical • hard

Explain the Hub and Spoke network topology in Azure or AWS. Why is it preferred over a full-mesh VPC peering setup for large enterprises?

#Hub and Spoke #Transit Gateway #VPC Peering #Enterprise Networking

Practice

Cloud Engineer • Technical • medium

How do you handle secrets management (e.g., API keys, database passwords) in a CI/CD pipeline and within a Kubernetes environment?

#Secrets Management #HashiCorp Vault #Azure Key Vault #AWS Secrets Manager

Practice

Cloud Engineer • Technical • medium

You are paged because a critical microservice pod in an EKS/AKS cluster is stuck in a 'CrashLoopBackOff' state. Walk me through your exact troubleshooting steps.

#Kubernetes #Troubleshooting #Logging #Monitoring

Practice

Cloud Engineer • Technical • medium

In Kubernetes, what is the difference between a Deployment and a StatefulSet? Give a real-world enterprise use case for a StatefulSet.

#Kubernetes #StatefulSet #Deployment #Microservices

Practice

Cloud Engineer • Technical • medium

How do you secure an AWS S3 bucket or Azure Blob Storage account from public access while ensuring a specific Virtual Network (VNet) or VPC can still access it?

#Cloud Storage #VPC Endpoints #Private Link #IAM

Practice

Cloud Engineer • Technical • medium

A client wants to load balance traffic for a highly scalable web application and a backend database cluster. Explain the difference between an Application Load Balancer (ALB) and a Network Load Balancer (NLB), and when to use which.

#AWS #Load Balancing #ALB #NLB #OSI Model

Practice

Cloud Engineer • Technical • medium

How do you handle state file management and locking in Terraform when working with a distributed team of cloud engineers?

#Terraform #State Management #Collaboration

Practice

Cloud Engineer • Technical • medium

Explain the difference between Terraform and native IaC tools like Azure ARM templates or AWS CloudFormation. Why would a DXC enterprise client choose one over the other?

#Terraform #Azure ARM #AWS CloudFormation #IaC

Practice

Cloud Engineer • Technical • hard

How do you manage IAM roles, policies, and security guardrails across hundreds of AWS accounts for a large enterprise client?

#AWS Organizations #SCP #IAM #Enterprise Governance

Practice

Cloud Engineer • Technical • medium

Explain the concept of an Azure Landing Zone or AWS Control Tower. Why is it a critical first step for DXC clients moving to the cloud?

#Landing Zones #AWS Control Tower #Governance #Cloud Adoption Framework

Practice

Cloud Engineer • Technical • medium

What are 'cold starts' in serverless computing (e.g., AWS Lambda), and how do you mitigate them for latency-sensitive applications?

#Serverless #AWS Lambda #Performance Optimization

Practice

Cloud Engineer • Technical • easy

Compare Amazon RDS Multi-AZ deployments with Read Replicas. When would you recommend one over the other to a client?

#AWS RDS #High Availability #Scalability #Databases

Practice

Cloud Engineer • Technical • hard

A client needs to migrate a 5TB on-premise SQL Server database to Azure SQL Managed Instance with near-zero downtime. How do you achieve this?

#Database Migration #Azure SQL #Zero Downtime #Azure Data Migration Service

Practice

Cloud Engineer • Technical • medium

How do you detect and manage configuration drift in an environment managed by Infrastructure as Code?

#Terraform #Configuration Drift #GitOps #Automation

Practice

Cloud Engineer • Technical • hard

A client has a legacy Windows application (.NET Framework) that they want to modernize. How do you approach containerizing this application for the cloud?

#Windows Containers #Docker #.NET #Modernization

Practice

Data Engineer • Behavioral • medium

Tell me about a time you had a disagreement with a client or stakeholder regarding technical requirements. How did you resolve it?

#Communication #Conflict Resolution #Consulting

Practice

Data Engineer • Behavioral • easy

Describe your experience working in an Agile/Scrum environment with globally distributed teams.

#Agile #Teamwork #Remote Work

Practice

Data Engineer • Behavioral • medium

How do you ensure data quality and governance in the pipelines you build?

#Data Quality #Governance #Best Practices

Practice

Data Engineer • Behavioral • medium

Tell me about a time you failed to meet a project deadline. What happened and what did you learn?

#Accountability #Continuous Improvement

Practice

Data Engineer • Behavioral • easy

Why do you want to work at DXC Technology as a Data Engineer?

#Company Knowledge #Motivation

Practice

Data Engineer • Behavioral • easy

How do you explain complex data engineering concepts, like data lakes or distributed computing, to non-technical business stakeholders?

#Communication #Stakeholder Management

Practice

Data Engineer • Behavioral • medium

Describe a time you optimized a data pipeline and saved the company or client money.

#Optimization #Cost Reduction #Impact

Practice

Data Engineer • Behavioral • medium

How do you manage scope creep in the middle of a complex data migration project?

#Project Management #Client Management #Agile

Practice

Data Engineer • Coding • medium

Write a SQL query to find the second highest salary from an Employee table without using the LIMIT or TOP keywords.

#SQL #Subqueries #Aggregations

Practice

Data Engineer • Coding • medium

Write a PySpark snippet to group a dataframe by 'department' and calculate the average salary and total employee count for each.

#PySpark #Aggregations #DataFrames

Practice

Data Engineer • Coding • easy

Write a Python script using Pandas or PySpark to read a CSV file, filter out rows where the 'status' column is 'failed', and write the output to a Parquet file.

#Python #Pandas #PySpark #ETL

Practice

Data Engineer • Coding • medium

Write a Python function to parse a large server log file and return the top 5 most frequent IP addresses.

#Python #File I/O #Hash Maps #Collections

Practice

Data Engineer • Coding • medium

Write a Python generator function that reads a file and yields one line at a time. Why is this useful?

#Python #Generators #Memory Management

Practice

Data Engineer • Coding • medium

Write a SQL query to calculate the cumulative sum of sales by month for each region.

#SQL #Window Functions #Data Aggregation

Practice

Data Engineer • Coding • easy

Given a list of dictionaries representing employee records, write a Python function to sort the list by the 'salary' key in descending order.

#Python #Sorting #Data Structures

Practice

Data Engineer • System Design • medium

Explain the Lambda Architecture. What are its pros and cons compared to the Kappa Architecture?

#Data Architecture #Batch Processing #Stream Processing

Practice

Data Engineer • System Design • hard

Design an ETL pipeline to migrate daily transactional data from an on-premise SQL Server to an AWS S3 data lake, and then to Redshift for reporting.

#AWS #ETL Architecture #Data Lake #Redshift

Practice

Data Engineer • System Design • hard

Design a Data Lakehouse architecture for a large retail client. How does it differ from a traditional Data Lake?

#Data Lakehouse #Databricks #Delta Lake #Architecture

Practice

Data Engineer • System Design • hard

How would you design a real-time streaming pipeline to process IoT sensor data and generate alerts for anomalies?

#Streaming #Kafka #Spark Streaming #Real-time Processing

Practice

Data Engineer • Technical • easy

Explain the difference between RANK(), DENSE_RANK(), and ROW_NUMBER() in SQL. Provide a scenario where you would use each.

#SQL #Window Functions

Practice

Data Engineer • Technical • medium

Compare Azure Data Factory (ADF) and Azure Databricks. In a modern data stack, how do they complement each other?

#Azure #ADF #Databricks #ETL

Practice

Data Engineer • Technical • hard

Explain the concept of 'salting' in PySpark. Write a conceptual code snippet showing how you would implement it to fix a skewed join.

#PySpark #Data Skew #Advanced Optimization

Practice

Data Engineer • Technical • medium

What is the difference between a Common Table Expression (CTE) and a Temporary Table? When would you use one over the other?

#SQL #Database Architecture #Performance

Practice

Data Engineer • Technical • medium

How do you handle task dependencies and retries in Apache Airflow?

#Airflow #Orchestration #DAGs

Practice

Data Engineer • Technical • medium

What is the optimal file size for storing data in Amazon S3 for querying with Athena or Spark? Why?

#AWS S3 #Big Data Storage #Performance Optimization

Practice

Data Engineer • Technical • medium

How does Snowflake handle data storage and indexing? Explain the concept of micro-partitions.

#Snowflake #Cloud Data Warehousing #Micro-partitions

Practice

Data Engineer • Technical • medium

In AWS, when would you choose to use AWS Glue versus Amazon EMR for your data transformation workloads?

#AWS #Glue #EMR #Serverless

Practice

Data Engineer • Technical • medium

Explain Slowly Changing Dimensions (SCD). How do you implement an SCD Type 2 in an ETL pipeline?

#Data Warehousing #ETL #SCD

Practice

Data Engineer • Technical • medium

What is the difference between a Star Schema and a Snowflake Schema? Which one would you prefer for a modern cloud data warehouse?

#Data Warehousing #Dimensional Modeling

Practice

Data Engineer • Technical • easy

Explain lazy evaluation in Apache Spark. Why is it beneficial?

#Spark Architecture #DAG #Transformations vs Actions

Practice

Data Engineer • Technical • hard

During a PySpark job, you notice that one task takes significantly longer than the others, causing a bottleneck. What is the likely cause and how do you fix it?

#PySpark #Data Skew #Troubleshooting

Practice

Data Engineer • Technical • medium

What is a Broadcast Join in Spark? How does it improve performance compared to a Sort Merge Join?

#PySpark #Joins #Distributed Computing

Practice

Data Engineer • Technical • medium

Explain the difference between Repartition and Coalesce in PySpark. When would you use one over the other?

#PySpark #Data Partitioning #Performance Optimization

Practice

Data Engineer • Technical • medium

How would you handle processing a 50GB file in Python on a machine with only 8GB of RAM?

#Python #Generators #Memory Management #Chunking

Practice

Data Engineer • Technical • medium

You have a query that is taking too long to execute. Walk me through the steps you would take to optimize it.

#Performance Tuning #Execution Plans #Indexing

Practice

Data Scientist • Behavioral • easy

Describe a project where you had to collaborate closely with Data Engineers and DevOps/MLOps teams to deliver a solution.

#Teamwork #Cross-functional Collaboration #Agile

Practice

Data Scientist • Behavioral • medium

Tell me about a time you had to explain a highly technical machine learning concept to a non-technical client or business stakeholder.

#Stakeholder Management #Communication #Consulting

Practice

Data Scientist • Behavioral • medium

Describe a time when a client had unrealistic expectations about what AI/ML could achieve for their legacy systems. How did you manage the situation?

#Client Management #Conflict Resolution #Expectation Management

Practice

Data Scientist • Behavioral • medium

Tell me about a time you received a dataset from a client that was completely undocumented and messy. How did you proceed?

#Data Exploration #Client Communication #Ambiguity

Practice

Data Scientist • Behavioral • medium

Tell me about a time a machine learning model you built failed or underperformed in production. What was the root cause and how did you fix it?

#Failure Analysis #Continuous Improvement #Accountability

Practice

Data Scientist • Behavioral • easy

Why do you want to work as a Data Scientist at DXC Technology specifically?

#Company Knowledge #Motivation #Career Goals

Practice

Data Scientist • Coding • easy

Write a Python script using Pandas to merge two large datasets (e.g., client CRM data and transaction logs), handle missing values, and group by a specific category to find the sum.

#Python #Pandas #Data Cleaning

Practice

Data Scientist • Coding • easy

Given an array of integers and a target sum, write a Python function to return the indices of the two numbers that add up to the target. (Two Sum)

#Python #Hash Maps #Time Complexity

Practice

Data Scientist • Coding • hard

Implement the K-Means clustering algorithm from scratch in Python. You do not need to optimize it, but the logic must be sound.

#Python #Machine Learning Algorithms #Math

Practice

Data Scientist • Coding • hard

Write a SQL query to find the retention rate of users. Specifically, find the percentage of users who logged in on day 1 and also logged in on day 2.

#SQL #Self Joins #Cohort Analysis #Product Analytics

Practice

Data Scientist • Coding • medium

Write a SQL query to find the top 3 highest-paid employees in each department. Handle ties appropriately.

#SQL #Window Functions #Ranking

Practice

Data Scientist • Coding • medium

Write a SQL query using window functions to calculate the 7-day rolling average of daily transaction volumes for a specific enterprise client.

#SQL #Window Functions #Data Aggregation

Practice

Data Scientist • Coding • medium

Write a Python function from scratch to calculate the TF-IDF scores for a given list of documents without using Scikit-Learn.

#Python #NLP #Math Implementation

Practice

Data Scientist • Coding • medium

Write a SQL query to calculate the cumulative sum of revenue per month for the year 2023.

#SQL #Window Functions #Cumulative Sum

Practice

Data Scientist • System Design • medium

If a client wants to migrate their on-premise machine learning workloads to the cloud, how would you evaluate whether to use AWS SageMaker vs Azure Machine Learning?

#Cloud Computing #AWS #Azure #MLOps

Practice

Data Scientist • System Design • medium

Design a system to automatically categorize and route incoming IT support tickets to the correct resolution team using machine learning.

#NLP #Text Classification #API Design #Enterprise Architecture

Practice

Data Scientist • System Design • hard

Design an end-to-end architecture for deploying a predictive maintenance model for a manufacturing client. How do you get data from IoT sensors to the model and return predictions?

#IoT #MLOps #Cloud Architecture #Streaming

Practice

Data Scientist • System Design • hard

Design an NLP pipeline to extract key clauses and entities from thousands of scanned legacy PDF contracts for a legal client.

#NLP #OCR #Information Extraction #LLMs

Practice

Data Scientist • System Design • hard

Design a real-time anomaly detection system for network security logs. The system must process 100,000 events per second.

#Streaming #Anomaly Detection #Scalability #Cybersecurity

Practice

Data Scientist • System Design • medium

How would you monitor a deployed machine learning model for concept drift and data drift? What steps would you take if drift is detected?

#Model Monitoring #Concept Drift #Data Drift #Production ML

Practice

Data Scientist • Technical • easy

Explain the Bias-Variance tradeoff. How does regularizing a model affect its bias and variance?

#Model Evaluation #Regularization #Statistical Theory

Practice

Data Scientist • Technical • easy

What is the time complexity of looking up a value in a Python list versus a Python dictionary? Why?

#Python #Time Complexity #Hash Tables

Practice

Data Scientist • Technical • medium

Compare ARIMA and Prophet for time series forecasting. What are the pros and cons of each?

#ARIMA #Prophet #Forecasting

Practice

Data Scientist • Technical • medium

Explain the kernel trick in Support Vector Machines (SVM). Name two common kernels and when you would use them.

#SVM #Algorithms #Math

Practice

Data Scientist • Technical • hard

Explain the self-attention mechanism in Transformer models. Why has it largely replaced RNNs for NLP tasks?

#NLP #Transformers #Attention Mechanism #LLMs

Practice

Data Scientist • Technical • easy

What are the most effective techniques for detecting outliers in a multi-dimensional dataset?

#Outlier Detection #Isolation Forest #Z-score

Practice

Data Scientist • Technical • medium

What is multicollinearity in a regression model? How do you detect it, and how do you resolve it?

#Linear Regression #VIF #Feature Engineering

Practice

Data Scientist • Technical • medium

When evaluating a binary classifier, when would you prefer the Precision-Recall curve over the ROC curve?

#ROC-AUC #Precision-Recall #Imbalanced Data

Practice

Data Scientist • Technical • medium

Why can't you use standard k-fold cross-validation for time series forecasting? What should you use instead?

#Cross-Validation #Time Series #Model Evaluation

Practice

Data Scientist • Technical • easy

What are your strategies for handling missing data in a dataset provided by a client? How do you decide between imputation and dropping rows?

#Data Cleaning #Imputation #EDA

Practice

Data Scientist • Technical • hard

How do you scale a machine learning data preparation pipeline when the dataset is too large to fit into a single machine's RAM? Explain how you would use PySpark.

#PySpark #Distributed Computing #Big Data

Practice

Data Scientist • Technical • medium

Explain the concept of statistical power and p-values in the context of A/B testing a new feature on an enterprise web portal.

#A/B Testing #Hypothesis Testing #P-value

Practice

Data Scientist • Technical • medium

What is the mathematical difference between L1 (Lasso) and L2 (Ridge) regularization? When would you use L1 over L2?

#Regularization #Linear Models #Feature Selection

Practice

Data Scientist • Technical • medium

Explain the difference between Random Forest and Gradient Boosting. In what scenario would you choose one over the other for a client's predictive model?

#Ensemble Methods #Random Forest #XGBoost #Model Selection

Practice

Data Scientist • Technical • medium

We often work with clients in the financial sector. How would you handle a highly imbalanced dataset for a credit card fraud detection model?

#Imbalanced Data #SMOTE #Class Weights #Fraud Detection

Practice

DevOps Engineer • Behavioral • easy

Tell me about a time you had to learn a new technology quickly to meet a client's project deadline.

#Learning #Time Management #Consulting

Practice

DevOps Engineer • Behavioral • medium

Tell me about a time you had to migrate a legacy monolithic application to a containerized microservices architecture. What challenges did you face?

#Migration #Microservices #Docker #Problem Solving

Practice

DevOps Engineer • Behavioral • hard

DXC works with many clients who have strict change management processes. How do you balance the need for agile DevOps practices with ITIL/ITSM compliance?

#ITIL #Agile #Change Management #Enterprise

Practice

DevOps Engineer • Behavioral • medium

Describe a situation where a production deployment failed during a critical client release. How did you handle the rollback and communication?

#Incident Management #Communication #Rollbacks

Practice

DevOps Engineer • Coding • hard

Write an Ansible playbook snippet to patch a fleet of RHEL servers and reboot them only if the kernel was updated.

#Ansible #Linux #Patch Management

Practice

DevOps Engineer • Coding • medium

Write a Python script using Boto3 to find and delete all unattached EBS volumes older than 30 days to optimize client cloud costs.

#Python #AWS #Boto3 #Cost Optimization

Practice

DevOps Engineer • Coding • medium

Write a Python function to check the health endpoint of a list of URLs and send an alert to a Slack webhook if any return a non-200 status code.

#Python #Monitoring #Automation

Practice

DevOps Engineer • Coding • medium

Write a Bash script to parse an Nginx access log and output the top 10 IP addresses making the most requests.

#Bash #Linux #Log Parsing

Practice

DevOps Engineer • System Design • hard

A client wants to migrate their on-premise data center to Azure. Walk me through the steps and tools you would use to assess and migrate their VMs and databases.

#Cloud Migration #Azure #Architecture

Practice

DevOps Engineer • System Design • hard

Design a highly available, multi-region CI/CD architecture for a global banking client that requires strict compliance and zero downtime deployments.

#High Availability #CI/CD #Architecture #Compliance

Practice

DevOps Engineer • System Design • hard

Design a disaster recovery strategy for a stateful application hosted on AWS, ensuring an RPO of 15 minutes and RTO of 1 hour.

#Disaster Recovery #AWS #Architecture

Practice

DevOps Engineer • Technical • medium

How do you optimize a Dockerfile to reduce the image size and improve build times for a Java Spring Boot application?

#Docker #Optimization #Java

Practice

DevOps Engineer • Technical • easy

Explain the difference between git merge and git rebase. When would you use one over the other in a shared team repository?

#Git #Collaboration

Practice

DevOps Engineer • Technical • medium

How do you manage Terraform state files securely when working with multiple DevOps engineers on a large DXC client project?

#Terraform #State Management #AWS S3 #Azure Blob Storage

Practice

DevOps Engineer • Technical • medium

Explain how you would troubleshoot a CrashLoopBackOff error in a Kubernetes pod deployed on Azure Kubernetes Service (AKS).

#Kubernetes #AKS #Troubleshooting

Practice

DevOps Engineer • Technical • medium

How do you handle secrets management in Jenkins pipelines for enterprise clients with strict compliance requirements?

#Jenkins #Security #Secrets Management

Practice

DevOps Engineer • Technical • medium

You accidentally committed a file containing an AWS secret key to a public repository. What are your immediate next steps?

#Git #AWS #Incident Response

Practice

DevOps Engineer • Technical • medium

You encounter a 'state lock' error in Terraform. What causes this and how do you safely resolve it?

#Terraform #Troubleshooting

Practice

DevOps Engineer • Technical • medium

How do you centralize logs from multiple Docker containers running across different EC2 instances using the ELK stack?

#Logging #ELK #Docker

Practice

DevOps Engineer • Technical • hard

A Linux server is experiencing high load average but low CPU utilization. How do you troubleshoot this?

#Linux #Troubleshooting #Performance Tuning

Practice

DevOps Engineer • Technical • medium

How would you set up Prometheus and Grafana to monitor the JVM metrics of a client's legacy application?

#Prometheus #Grafana #Observability

Practice

DevOps Engineer • Technical • medium

How do you configure resource requests and limits in Kubernetes, and what happens if a container exceeds its memory limit?

#Kubernetes #Resource Management

Practice

DevOps Engineer • Technical • medium

Explain the DNS resolution process when a user types a URL into their browser until the IP address is resolved.

#DNS #Networking

Practice

DevOps Engineer • Technical • hard

How do you implement a Blue-Green deployment strategy using Jenkins and AWS ECS?

#AWS ECS #Jenkins #Deployment Strategies

Practice

DevOps Engineer • Technical • medium

What are Terraform modules, and how do you version control them for reuse across different client environments?

#Terraform #Modularity #Version Control

Practice

DevOps Engineer • Technical • medium

What is the difference between a Deployment and a StatefulSet in Kubernetes? Give a use case for each.

#Kubernetes #Architecture

Practice

DevOps Engineer • Technical • medium

How do you integrate security scanning (DevSecOps) into a GitLab CI pipeline?

#GitLab CI #DevSecOps #SAST/DAST

Practice

DevOps Engineer • Technical • medium

Explain how a VPC peering connection works. Can you route traffic through a peered VPC to the internet?

#AWS #VPC #Networking

Practice

DevOps Engineer • Technical • medium

Explain the concept of Ansible roles and how you use Ansible Galaxy in an enterprise environment.

#Ansible #Automation

Practice

DevOps Engineer • Technical • easy

How do you find which process is listening on a specific port in Linux?

#Linux #Networking

Practice

DevOps Engineer • Technical • medium

Explain how Ingress controllers work in Kubernetes and how you would secure an Ingress with TLS certificates.

#Kubernetes #Networking #Security

Practice

DevOps Engineer • Technical • easy

What is the difference between IAM Roles and IAM Policies? How do you assign permissions to an EC2 instance securely?

#AWS #IAM #Security

Practice

DevOps Engineer • Technical • medium

How do you share workspace data between different stages in a Jenkins declarative pipeline?

#Jenkins #Pipelines

Practice

DevOps Engineer • Technical • easy

What is the difference between CMD and ENTRYPOINT in a Dockerfile?

#Docker

Practice

DevOps Engineer • Technical • medium

Explain the difference between an Application Load Balancer (ALB) and a Network Load Balancer (NLB) in AWS. When would you use an NLB?

#AWS #Networking #Load Balancing

Practice

Frontend Engineer • Behavioral • medium

Describe a situation where you had to quickly learn a new frontend technology or framework to meet a project deadline.

#Adaptability #Learning #Agile

Practice

Frontend Engineer • Behavioral • medium

Tell me about a time you had to push back on a client's feature request because it would negatively impact frontend performance.

#Communication #Client Management #Performance

Practice

Frontend Engineer • Behavioral • hard

DXC often works with legacy codebases. Describe your approach to refactoring a poorly documented, legacy JavaScript application without breaking existing features.

#Refactoring #Legacy Code #Testing

Practice

Frontend Engineer • Behavioral • hard

Tell me about a time you identified a critical bug in production. How did you troubleshoot and resolve it under pressure?

#Problem Solving #Debugging #Incident Management

Practice

Frontend Engineer • Behavioral • medium

How do you handle disagreements with a backend developer regarding API contract designs?

#Collaboration #Conflict Resolution #API Design

Practice

Frontend Engineer • Coding • medium

Implement a polyfill for `Promise.all`.

#JavaScript #Asynchronous Programming #Promises

Practice

Frontend Engineer • Coding • easy

Explain event delegation in JavaScript. Write a snippet to handle click events on a dynamically generated list of items.

#DOM Manipulation #Events #JavaScript

Practice

Frontend Engineer • Coding • hard

Write a function to deep clone a nested JavaScript object, ensuring you handle circular references.

#JavaScript #Data Structures #Recursion

Practice

Frontend Engineer • Coding • easy

Migrate a legacy class-based React component with `componentDidMount` and `componentWillUnmount` to a functional component.

#React #Hooks #Refactoring

Practice

Frontend Engineer • Coding • medium

Implement a debounce function. Explain how it improves performance in a search input component.

#JavaScript #Performance #Closures

Practice

Frontend Engineer • Coding • hard

Write a custom TypeScript utility type `RequireOnlyOne<T, Keys>` that makes all properties of an object optional except one specific property.

#TypeScript #Advanced Types #Utility Types

Practice

Frontend Engineer • Coding • easy

What is semantic HTML? Refactor a given `div`-soup layout into semantic HTML5 tags.

#HTML #Semantics #Accessibility

Practice

Frontend Engineer • Coding • easy

Write the CSS to center a `div` both horizontally and vertically using Flexbox, and then using CSS Grid.

#CSS #Flexbox #Grid

Practice

Frontend Engineer • Coding • easy

Write a function that flattens a deeply nested array without using `Array.prototype.flat`.

#JavaScript #Arrays #Recursion

Practice

Frontend Engineer • Coding • medium

Design a custom React hook `useFetch` that handles loading, error, and caching states for API calls.

#React #Custom Hooks #API Integration

Practice

Frontend Engineer • Coding • medium

Write a Higher-Order Component (HOC) in React that restricts access to a route based on user roles.

#React #Security #HOC

Practice

Frontend Engineer • System Design • medium

Design an autocomplete search component. Discuss API debouncing, caching, and accessibility.

#Component Design #Performance #Accessibility

Practice

Frontend Engineer • System Design • hard

Design the frontend architecture for a large-scale enterprise dashboard that visualizes real-time financial data.

#Frontend Architecture #WebSockets #Performance

Practice

Frontend Engineer • System Design • hard

How would you design a micro-frontend architecture for a legacy monolithic application being modernized by DXC?

#Micro-frontends #Module Federation #Legacy Modernization

Practice

Frontend Engineer • System Design • hard

Design a scalable design system and component library to be used across multiple DXC client projects.

#Design Systems #Architecture #Reusability

Practice

Frontend Engineer • Technical • medium

How do you identify and handle memory leaks in a Single Page Application (SPA)?

#Performance #Memory Management #Debugging

Practice

Frontend Engineer • Technical • medium

How does the event loop work in JavaScript? Explain the difference between microtasks and macrotasks with examples.

#Event Loop #Concurrency #JavaScript

Practice

Frontend Engineer • Technical • easy

What are the differences between `interface` and `type` in TypeScript? When would you use one over the other in a large enterprise application?

#TypeScript #Type System #Architecture

Practice

Frontend Engineer • Technical • medium

Explain closures in JavaScript. Give a practical example of where you used them in a recent project.

#JavaScript #Closures #Scope

Practice

Frontend Engineer • Technical • medium

How does React's Virtual DOM work, and how does the reconciliation algorithm optimize UI updates?

#React #Virtual DOM #Performance

Practice

Frontend Engineer • Technical • medium

In React, explain the difference between `useMemo` and `useCallback`. Describe a scenario where using them actually degrades performance.

#React #Hooks #Performance Optimization

Practice

Frontend Engineer • Technical • medium

How do you manage global state in a large-scale React application? Compare Redux Toolkit and the Context API.

#React #State Management #Redux

Practice

Frontend Engineer • Technical • medium

Explain the component lifecycle in Angular. How do you clean up RxJS subscriptions to prevent memory leaks?

#Angular #RxJS #Lifecycle Hooks

Practice

Frontend Engineer • Technical • medium

How does Angular's Dependency Injection work? Explain the difference between `providedIn: 'root'` and providing a service at the component level.

#Angular #Dependency Injection #Architecture

Practice

Frontend Engineer • Technical • medium

Explain Server-Side Rendering (SSR) vs Client-Side Rendering (CSR). Why might DXC recommend SSR for a client's public-facing e-commerce site?

#SSR #SEO #Web Performance

Practice

Frontend Engineer • Technical • hard

What are React Server Components? How do they differ from traditional Server-Side Rendering (SSR)?

#React #Server Components #Next.js

Practice

Frontend Engineer • Technical • medium

How do you optimize the initial load time of a heavy Single Page Application? Discuss code splitting, lazy loading, and asset optimization.

#Performance #Webpack #Optimization

Practice

Frontend Engineer • Technical • easy

Explain the CSS Box Model. How does `box-sizing: border-box` change its behavior?

#CSS #Layout #Fundamentals

Practice

Frontend Engineer • Technical • medium

What are the key principles of Web Accessibility (WCAG)? How do you ensure a complex data table is accessible to screen readers?

#Accessibility #HTML #WCAG

Practice

Frontend Engineer • Technical • medium

Explain CSS specificity and how you avoid specificity wars in a large enterprise codebase.

#CSS #Architecture #Best Practices

Practice

Full Stack Engineer • Behavioral • medium

Give an example of how you optimized an existing legacy codebase. What metrics did you use to measure success?

#Refactoring #Performance #Legacy Systems

Practice

Full Stack Engineer • Behavioral • easy

Describe a situation where you had to quickly learn a new technology or framework to deliver a project on time.

#Continuous Learning #Problem Solving

Practice

Full Stack Engineer • Behavioral • medium

Tell me about a time you had to push back on a client's unrealistic technical requirement. How did you handle the communication?

#Communication #Stakeholder Management #Agile

Practice

Full Stack Engineer • Behavioral • hard

Tell me about a time you identified a major bug in production. How did you troubleshoot and resolve it?

#Debugging #Incident Management #Accountability

Practice

Full Stack Engineer • Behavioral • medium

Describe your experience working in Agile/Scrum teams across different time zones. How do you ensure effective collaboration?

#Agile #Communication #Remote Work

Practice

Full Stack Engineer • Behavioral • medium

How do you handle disagreements with a senior developer regarding architectural choices?

#Conflict Resolution #Communication #Leadership

Practice

Full Stack Engineer • Behavioral • easy

Why do you want to work for DXC Technology, and how does your experience align with our focus on enterprise digital transformation?

#Company Knowledge #Career Goals

Practice

Full Stack Engineer • Coding • easy

Given an array of integers nums and an integer target, return indices of the two numbers such that they add up to target.

#Arrays #Hash Tables

Practice

Full Stack Engineer • Coding • easy

Find the first non-repeating character in a string and return its index. If it does not exist, return -1.

#Strings #Hash Tables

Practice

Full Stack Engineer • Coding • medium

Write a function to flatten a deeply nested JSON object into a single-level dictionary with dot-separated keys.

#Recursion #Data Structures #JSON

Practice

Full Stack Engineer • Coding • medium

Implement a debounce function in JavaScript that delays invoking a provided function until after 'wait' milliseconds have elapsed.

#JavaScript #Closures #Asynchronous Programming

Practice

Full Stack Engineer • Coding • medium

Write a function to merge an array of overlapping intervals into a new array of non-overlapping intervals.

#Arrays #Sorting

Practice

Full Stack Engineer • Coding • medium

Given a string s, find the length of the longest substring without repeating characters.

#Strings #Sliding Window #Hash Tables

Practice

Full Stack Engineer • Coding • easy

Given a string containing just the characters '(', ')', '{', '}', '[' and ']', determine if the input string is valid.

#Strings #Stacks

Practice

Full Stack Engineer • Coding • medium

Write a SQL query to find the second highest salary from an Employee table. If there is no second highest salary, return null.

#Database #Queries #Aggregation

Practice

Full Stack Engineer • Coding • medium

Implement an LRU (Least Recently Used) Cache. It should support get and put operations in O(1) time complexity.

#Hash Tables #Linked Lists #Design

Practice

Full Stack Engineer • System Design • hard

Design a scalable notification system capable of sending millions of emails, SMS, and push notifications daily for an enterprise client.

#Message Queues #Microservices #Scalability

Practice

Full Stack Engineer • System Design • medium

Design a URL shortener service like Bitly. How do you ensure uniqueness and handle high read volumes?

#Hashing #Caching #Scalability

Practice

Full Stack Engineer • System Design • medium

Design a centralized logging and monitoring architecture for a distributed microservices ecosystem.

#Observability #DevOps #Microservices

Practice

Full Stack Engineer • System Design • hard

Design a legacy-to-cloud migration strategy for a monolithic on-premise application. How do you ensure zero downtime for the client?

#Cloud Migration #Microservices #Strangler Fig Pattern

Practice

Full Stack Engineer • System Design • hard

Design an e-commerce checkout service that handles high concurrency during a Black Friday sale.

#Concurrency #Distributed Systems #Databases

Practice

Full Stack Engineer • Technical • medium

What are Java Streams and how do they differ from Collections? Provide an example of when you would use them.

#Java #Functional Programming

Practice

Full Stack Engineer • Technical • medium

How does React's Virtual DOM work, and how does the reconciliation algorithm (Fiber) improve performance?

#React #JavaScript #Performance

Practice

Full Stack Engineer • Technical • hard

Explain the difference between clustered and non-clustered indexes. When would you use one over the other in an enterprise database?

#SQL Server #Performance Tuning #Indexing

Practice

Full Stack Engineer • Technical • easy

Explain CORS (Cross-Origin Resource Sharing). How do you configure it in a backend API, and why is it necessary?

#HTTP #Security #Browsers

Practice

Full Stack Engineer • Technical • medium

Explain the difference between React's useMemo and useCallback hooks. When should you avoid using them?

#React #Performance Optimization

Practice

Full Stack Engineer • Technical • hard

How do you handle database migrations in a CI/CD pipeline without causing downtime?

#CI/CD #Database #Deployment

Practice

Full Stack Engineer • Technical • hard

Describe the lifecycle of a Spring Bean from instantiation to destruction.

#Java #Spring Framework #Architecture

Practice

Full Stack Engineer • Technical • medium

How do you handle state management in a large-scale React application?

#React #Redux #Context API

Practice

Full Stack Engineer • Technical • medium

What are the differences between monolithic and microservices architectures? When would you recommend a monolith over microservices?

#Microservices #System Design #Software Architecture

Practice

Full Stack Engineer • Technical • medium

How does the event loop work in Node.js, and how does it handle asynchronous operations?

#Node.js #Asynchronous Programming #Architecture

Practice

Full Stack Engineer • Technical • medium

What are the main differences between running applications in Docker containers versus Virtual Machines?

#Docker #Virtualization #Cloud

Practice

Full Stack Engineer • Technical • hard

How do you optimize the performance of a slow-loading web application? Walk me through your diagnostic steps.

#Performance #Frontend #Networking

Practice

Full Stack Engineer • Technical • medium

Explain the concept of JWT (JSON Web Tokens). How do you secure a REST API using JWT, and what are the security risks?

#Authentication #Authorization #Web Security

Practice

Full Stack Engineer • Technical • medium

What is Dependency Injection, and how is it implemented in Spring Boot (or .NET Core)?

#Java #Spring Boot #Design Patterns #C#

Practice

Machine Learning Engineer • Behavioral • easy

How do you prioritize tasks when working on multiple client deliverables with tight, overlapping deadlines?

#Prioritization #Consulting #Agile

Practice

Machine Learning Engineer • Behavioral • easy

Why do you want to work at DXC Technology, and how does your ML experience align with our enterprise IT and consulting focus?

#Company Knowledge #Motivation #Consulting

Practice

Machine Learning Engineer • Behavioral • medium

Tell me about a time you had to work with messy, undocumented legacy data to build a predictive model.

#Data Cleaning #Legacy Systems #Resilience

Practice

Machine Learning Engineer • Behavioral • medium

Describe your experience working in an Agile environment. How do you estimate time for ML research tasks, which are inherently uncertain?

#Agile #Estimation #Research

Practice

Machine Learning Engineer • Behavioral • medium

Tell me about a time you identified a bottleneck in an existing data or ML pipeline and optimized it.

#Optimization #Performance Tuning #Initiative

Practice

Machine Learning Engineer • Behavioral • medium

How do you handle scope creep when a client keeps asking for additional features or metrics in an ongoing ML pipeline project?

#Client Management #Scope Management #Agile

Practice

Machine Learning Engineer • Behavioral • medium

Describe a project where you had to quickly learn a new ML framework or cloud technology to meet client needs.

#Continuous Learning #Cloud Platforms #Consulting

Practice

Machine Learning Engineer • Behavioral • medium

Tell me about a time you disagreed with a senior engineer or architect about a technical approach. How did you handle it?

#Conflict Resolution #Teamwork #Professionalism

Practice

Machine Learning Engineer • Behavioral • medium

Describe a situation where your machine learning model performed well in training but failed or underperformed in production. How did you resolve it?

#Troubleshooting #Production Issues #Lessons Learned

Practice

Machine Learning Engineer • Behavioral • medium

Tell me about a time you had to explain a complex machine learning model to a non-technical client or stakeholder.

#Client Facing #Stakeholder Management #Explainable AI

Practice

Machine Learning Engineer • Coding • easy

Write a Python function to merge two sorted arrays into a single sorted array without using built-in sorting functions.

#Python #Arrays #Two Pointers

Practice

Machine Learning Engineer • Coding • easy

Write a Python function using pandas to impute missing values in a dataset: numerical columns with the median and categorical columns with the mode.

#Python #Pandas #Data Cleaning

Practice

Machine Learning Engineer • Coding • hard

Write a Python function to calculate the ROC-AUC score given an array of true labels and an array of predicted probabilities, without using scikit-learn.

#Python #Metrics #Machine Learning Algorithms

Practice

Machine Learning Engineer • Coding • hard

Implement a basic K-Means clustering algorithm from scratch in Python using NumPy.

#Python #NumPy #Machine Learning Algorithms

Practice

Machine Learning Engineer • Coding • medium

Write a SQL query to identify clients who have a churn probability greater than 0.8 and have not logged in for the past 30 days, joining a predictions table and a user_activity table.

#SQL #Joins #Filtering

Practice

Machine Learning Engineer • Coding • medium

Write a SQL query to calculate the 7-day rolling average of model inference latency times from a logs table.

#SQL #Window Functions #Time Series

Practice

Machine Learning Engineer • Coding • medium

Write a Python script to perform a grid search over hyperparameters for an XGBoost model, utilizing cross-validation.

#Python #XGBoost #Hyperparameter Tuning #Cross-Validation

Practice

Machine Learning Engineer • Coding • medium

Given a list of customer transaction amounts, write a Python script to find the top K most frequent transaction values.

#Python #Hash Maps #Heaps

Practice

Machine Learning Engineer • System Design • hard

Design a machine learning system to predict server and hardware failures in a large enterprise data center (Predictive Maintenance).

#Predictive Maintenance #IoT Data #Streaming Architecture

Practice

Machine Learning Engineer • System Design • medium

How do you ensure data privacy and compliance (like GDPR or HIPAA) when training machine learning models on sensitive client data?

#Data Privacy #GDPR #Data Anonymization

Practice

Machine Learning Engineer • System Design • medium

Design a batch processing pipeline using PySpark to score millions of customer records nightly for a marketing campaign.

#PySpark #Batch Processing #Big Data

Practice

Machine Learning Engineer • System Design • medium

How do you handle A/B testing for a newly deployed recommendation model on an e-commerce platform?

#A/B Testing #Recommendation Systems #Experimentation

Practice

Machine Learning Engineer • System Design • hard

Design an enterprise document search system using Large Language Models (LLMs) and Vector Databases (RAG architecture).

#LLMs #RAG #Vector Databases #NLP

Practice

Machine Learning Engineer • System Design • medium

Explain your approach to monitoring model drift in a production environment. How do you decide when to trigger retraining?

#Model Monitoring #Data Drift #Concept Drift

Practice

Machine Learning Engineer • System Design • hard

Design a real-time fraud detection system for a banking client processing thousands of transactions per second.

#Fraud Detection #Real-time Processing #Scalability

Practice

Machine Learning Engineer • System Design • medium

How would you deploy a machine learning model as a highly available REST API using Docker and Kubernetes?

#Docker #Kubernetes #Model Deployment #API

Practice

Machine Learning Engineer • Technical • medium

How do you handle highly imbalanced datasets, such as those found in enterprise fraud detection?

#Data Imbalance #Fraud Detection #Metrics

Practice

Machine Learning Engineer • Technical • medium

Explain the bias-variance tradeoff. How does it apply to Random Forests compared to single Decision Trees?

#Ensemble Methods #Model Evaluation #Theory

Practice

Machine Learning Engineer • Technical • easy

Explain the difference between bagging and boosting ensemble methods.

#Ensemble Methods #Bagging #Boosting

Practice

Machine Learning Engineer • Technical • medium

What is data leakage in machine learning? Give an example of how it might occur during feature engineering and how to prevent it.

#Data Leakage #Feature Engineering #Best Practices

Practice

Machine Learning Engineer • Technical • medium

How do you evaluate the performance of an unsupervised learning model like K-Means clustering?

#Unsupervised Learning #Clustering #Metrics

Practice

Machine Learning Engineer • Technical • hard

Explain the architecture of a Transformer model. Why has it largely replaced LSTMs for enterprise NLP tasks?

#NLP #Transformers #Attention Mechanism

Practice

Machine Learning Engineer • Technical • easy

How does L1 (Lasso) regularization differ from L2 (Ridge) regularization mathematically and practically?

#Regularization #Feature Selection

Practice

Machine Learning Engineer • Technical • medium

What are the core assumptions of linear regression, and how do you validate them before deploying a model?

#Linear Regression #Statistics

Practice

Machine Learning Engineer • Technical • hard

Explain how Gradient Boosting works. What are the key differences between XGBoost and LightGBM?

#Boosting #XGBoost #LightGBM

Practice

Product Manager • Behavioral • medium

How do you balance custom feature requests from a major enterprise client against the core product roadmap?

#Stakeholder Management #Prioritization #B2B Product Management

Practice

Product Manager • Behavioral • easy

Why DXC Technology, and how does our focus on enterprise digital transformation align with your career goals?

#Company Knowledge #Career Trajectory #Digital Transformation

Practice

Product Manager • Behavioral • medium

What is your approach to managing and prioritizing technical debt alongside new feature development?

#Technical Debt #Roadmap Planning #Engineering Collaboration

Practice

Product Manager • Behavioral • medium

Describe a time you had to say 'no' to a senior executive or key stakeholder regarding a product feature.

#Stakeholder Management #Conflict Resolution #Prioritization

Practice

Product Manager • Behavioral • medium

Explain your approach to sprint planning and backlog grooming with a globally distributed, offshore engineering team.

#Agile/Scrum #Remote Collaboration #Cross-functional Teams

Practice

Product Manager • Behavioral • medium

Tell me about a time a product release failed in a production environment. How did you handle it?

#Incident Management #Accountability #Post-mortems

Practice

Product Manager • Behavioral • medium

Tell me about a time you had to pivot your product strategy due to a sudden shift in market conditions or client budget cuts.

#Adaptability #Strategic Thinking #Risk Management

Practice

Product Manager • Behavioral • medium

Tell me about a time you worked on modernizing a legacy enterprise system. What were the biggest challenges?

#Legacy Modernization #Change Management #Risk Mitigation

Practice

Product Manager • Behavioral • medium

Describe your process for conducting user research when your end-users are highly technical system administrators.

#User Research #Technical Personas #B2B UX

Practice

Product Manager • Behavioral • easy

How do you stay updated on rapid changes in enterprise IT trends, such as Generative AI and Zero Trust Security?

#Continuous Learning #Industry Trends #Technology Landscape

Practice

Product Manager • Behavioral • medium

Tell me about a time you identified a new market opportunity for an existing IT service. How did you validate it?

#Market Research #Innovation #Validation

Practice

Product Manager • Behavioral • hard

What is your strategy for sunsetting a legacy enterprise product that still generates revenue but is too costly to maintain?

#Product Lifecycle #Sunsetting #Client Communication #Migration

Practice

Product Manager • Behavioral • medium

Tell me about a time you used data to resolve a technical disagreement with an engineering lead.

#Conflict Resolution #Data-Driven Decisions #Engineering Collaboration

Practice

Product Manager • Behavioral • medium

Describe a time you collaborated with Sales and Marketing to define the Go-To-Market (GTM) strategy for a new technical product.

#Go-To-Market #Cross-functional Collaboration #Sales Enablement

Practice

Product Manager • Coding • medium

Write a SQL query to find the average time it takes to resolve a critical severity IT support ticket, grouped by client.

#Data Aggregation #ITSM Metrics #Performance Tracking

Practice

Product Manager • Coding • medium

Write a SQL query to find the top 5 enterprise clients by monthly recurring revenue (MRR) who have an active 'CloudRight' subscription.

#Data Extraction #Revenue Metrics #Database Querying

Practice

Product Manager • Coding • easy

Write a SQL query to identify users who have an active license but haven't logged into the enterprise portal in the last 90 days.

#User Engagement #Data Extraction #Filtering

Practice

Product Manager • Coding • hard

Write a SQL query to calculate the month-over-month churn rate of our SaaS enterprise offering.

#Data Analytics #Churn #Window Functions

Practice

Product Manager • System Design • hard

Design a cloud migration dashboard for enterprise clients transitioning from on-premise to AWS/Azure.

#Cloud Infrastructure #UX/UI #Enterprise Software #Data Visualization

Practice

Product Manager • System Design • hard

Design a disaster recovery and business continuity reporting tool for enterprise clients.

#Disaster Recovery #Enterprise Security #Reporting #High Availability

Practice

Product Manager • System Design • hard

How would you design a scalable Identity and Access Management (IAM) solution for a client with 100,000+ employees across multiple geographies?

#IAM #Security #Scalability #Enterprise Architecture

Practice

Product Manager • System Design • hard

Design a billing and invoicing engine for a usage-based enterprise cloud service.

#Billing Systems #Usage Metering #Financial Software #Scalability

Practice

Product Manager • System Design • hard

How would you architect a data pipeline for ingesting and processing client telemetry data from thousands of IoT devices?

#Data Pipelines #IoT #Streaming Data #Scalability

Practice

Product Manager • System Design • hard

Design a system for monitoring SLA (Service Level Agreement) compliance across multiple third-party cloud providers for a single client.

#Monitoring #Cloud Architecture #SLAs #Data Aggregation

Practice

Product Manager • System Design • hard

Design an automated IT Service Management (ITSM) ticketing system that uses AI to route tickets to the correct support tier.

#AI/ML Integration #ITSM #Workflow Automation #Scalability

Practice

Product Manager • Technical • medium

How do you evaluate a 'build vs. buy' decision for a new data analytics feature requested by the sales team?

#Build vs Buy #Resource Allocation #Vendor Assessment

Practice

Product Manager • Technical • medium

If a major client reports a critical security vulnerability in your product, walk me through your immediate next steps.

#Incident Response #Cybersecurity #Client Communication

Practice

Product Manager • Technical • easy

Explain how REST APIs work to a non-technical enterprise client who is buying our integration services.

#APIs #Client Communication #Technical Translation

Practice

Product Manager • Technical • medium

How do you manage a product roadmap that relies heavily on third-party vendor APIs that frequently change or deprecate?

#Vendor Management #API Integration #Risk Management

Practice

Product Manager • Technical • hard

How do you ensure enterprise compliance standards (e.g., GDPR, HIPAA, SOC2) are built into the product lifecycle from day one?

#Data Privacy #Regulatory Compliance #Product Lifecycle

Practice

Product Manager • Technical • medium

How do you measure the success of an internal developer portal designed to accelerate digital transformation projects?

#KPIs #Internal Products #Developer Productivity

Practice

Product Manager • Technical • hard

How would you price a new cybersecurity managed service offering at DXC?

#Pricing Models #Go-To-Market #Cybersecurity #B2B Services

Practice

Product Manager • Technical • medium

How would you improve the onboarding experience for DXC's new enterprise clients to reduce time-to-value?

#User Experience #Onboarding #B2B SaaS #Time-to-Value

Practice

Product Manager • Technical • medium

Explain the difference between multi-tenant and single-tenant architecture and when you would recommend each to a B2B client.

#SaaS Architecture #Cloud Hosting #Enterprise Software

Practice

Product Manager • Technical • medium

Walk me through how you write a Product Requirements Document (PRD) for an internal API used by DXC's consulting teams.

#API Product Management #Documentation #Internal Tools

Practice

Software Engineer • Behavioral • easy

Describe a situation where you had to quickly learn a new technology or framework to complete a project on time.

#Learning #Time Management #Agile

Practice

Software Engineer • Behavioral • medium

How do you prioritize your tasks when dealing with multiple urgent requests from different client stakeholders?

#Prioritization #Communication #Stress Management

Practice

Software Engineer • Behavioral • medium

Tell me about a time you disagreed with a senior engineer or architect's design decision. How did you approach the situation?

#Conflict Resolution #Communication #Leadership

Practice

Software Engineer • Behavioral • easy

Explain your experience with Agile and Scrum methodologies. What ceremonies do you find most valuable and why?

#Agile #Scrum #Process

Practice

Software Engineer • Behavioral • easy

How do you ensure code quality and security in your deliverables before handing them over to a client?

#Testing #Code Review #Security

Practice

Software Engineer • Behavioral • medium

At DXC, you will often inherit legacy codebases from our enterprise clients. Tell me about a time you had to troubleshoot and refactor a critical bug in undocumented legacy code.

#Legacy Code #Debugging #Adaptability

Practice

Software Engineer • Behavioral • medium

Working in IT services means managing client expectations. Describe a time when a client requested a feature that was technically unfeasible or out of scope. How did you handle it?

#Communication #Negotiation #Stakeholder Management

Practice

Software Engineer • Coding • easy

Write a SQL query to find the second highest salary from an Employee table. If there is no second highest salary, return null.

#Databases #Aggregation

Practice

Software Engineer • Coding • easy

Given a string s containing just the characters '(', ')', '{', '}', '[' and ']', determine if the input string is valid.

#Stacks #Strings

Practice

Software Engineer • Coding • medium

Find the longest substring without repeating characters in a given string.

#Sliding Window #Hash Tables #Strings

Practice

Software Engineer • Coding • easy

Write a program to detect if a cycle exists in a linked list.

#Linked Lists #Two Pointers

Practice

Software Engineer • Coding • medium

Given an array of strings, group the anagrams together. You can return the answer in any order.

#Hash Tables #Strings #Sorting

Practice

Software Engineer • Coding • medium

Write a SQL query to find all employees who earn more than their managers.

#Databases #Joins

Practice

Software Engineer • Coding • easy

Implement a binary search algorithm to find a target value in a sorted array.

#Binary Search #Arrays

Practice

Software Engineer • Coding • medium

Given the root of a binary tree, return the level order traversal of its nodes' values. (i.e., from left to right, level by level).

#Trees #Breadth-First Search #Queues

Practice

Software Engineer • Coding • easy

Write a function to find the first non-repeating character in a string and return its index. If it doesn't exist, return -1.

#Strings #Hash Tables

Practice

Software Engineer • Coding • medium

Given an array of intervals where intervals[i] = [starti, endi], merge all overlapping intervals, and return an array of the non-overlapping intervals that cover all the intervals in the input.

#Arrays #Sorting

Practice

Software Engineer • System Design • hard

Design an inventory management system for a large e-commerce client. How do you handle concurrent purchases of the last item in stock?

#Concurrency #Databases #E-commerce

Practice

Software Engineer • System Design • hard

DXC frequently helps clients modernize legacy systems. Walk me through how you would design a strategy to migrate an on-premise monolithic application to a cloud-based microservices architecture.

#Microservices #Cloud Migration #Architecture

Practice

Software Engineer • System Design • medium

How would you design a distributed logging and monitoring system for an enterprise application consisting of 50+ microservices?

#Observability #Microservices #Infrastructure

Practice

Software Engineer • System Design • medium

Design a highly available URL Shortener service (like bit.ly).

#Scalability #Hashing #Databases

Practice

Software Engineer • System Design • medium

Explain how you would implement caching in a high-traffic enterprise application. What caching strategies would you use?

#Caching #Performance #Redis

Practice

Software Engineer • Technical • medium

What are the core differences between AWS S3 and AWS EBS? When would you use one over the other?

#AWS #Storage #Cloud

Practice

Software Engineer • Technical • medium

Explain the internal working of a HashMap in Java. What happens when a collision occurs?

#Data Structures #Hashing #Java

Practice

Software Engineer • Technical • easy

What are the key features introduced in Java 8? Can you provide an example of how you would use Streams to filter a list of objects?

#Java 8 #Streams #Lambdas

Practice

Software Engineer • Technical • medium

How does Spring Boot auto-configuration work? How can you disable a specific auto-configuration class?

#Spring Boot #Dependency Injection

Practice

Software Engineer • Technical • easy

Explain the difference between @Component, @Service, and @Repository annotations in Spring.

#Spring #Annotations

Practice

Software Engineer • Technical • medium

What are the SOLID principles of object-oriented design? Can you explain the Single Responsibility Principle with an example?

#OOP #Design Patterns #Clean Code

Practice

Software Engineer • Technical • easy

Explain the difference between an INNER JOIN and a LEFT JOIN in SQL. When would you use one over the other?

#Databases #Joins

Practice

Software Engineer • Technical • medium

How do you handle exceptions globally in a Spring Boot REST API?

#Spring Boot #REST #Exception Handling

Practice

Software Engineer • Technical • easy

What is the difference between REST and SOAP web services? Why has the industry largely moved towards REST?

#REST #SOAP #APIs

Practice

Software Engineer • Technical • medium

Explain the concept of a Virtual DOM in React. How does it improve performance?

#React #JavaScript #Performance

Practice

Software Engineer • Technical • hard

What is the difference between pessimistic and optimistic locking in database transactions?

#Concurrency #Transactions #SQL

Practice

Software Engineer • Technical • easy

Explain the benefits of Docker containerization. How does it improve the deployment process in a CI/CD pipeline?

#Docker #CI/CD #Deployment

Practice

Software Engineer • Technical • hard

How do you manage state and data consistency across distributed microservices when a single business transaction spans multiple services?

#Microservices #Distributed Systems #Transactions

Practice

DXC Technology

The Interview Loop

Recruiter Screen (30 min)

Technical Loop (3-4 Rounds)

Interview Question Bank

Tell me about a time you took the initiative to learn a new technology or tool because it was necessary for a project, even though it wasn't your core expertise.

At DXC, we frequently modernize legacy monolithic applications for enterprise clients. Tell me about a time you had to refactor or migrate a legacy system. What was your approach?

Describe a situation where you strongly disagreed with a senior engineer or architect on a technical decision. How did you handle it?

How do you ensure code quality and maintainability when working under strict deadlines in a fast-paced Agile sprint?

Tell me about a time you had to troubleshoot a critical production issue under severe pressure. Walk me through your debugging process.

DXC engineers often work directly with non-technical enterprise clients. Describe your experience gathering technical requirements from business stakeholders.

How do you balance the need to deliver new features quickly for a client versus the need to address accumulating technical debt?

Find the kth largest element in an unsorted array. Note that it is the kth largest element in the sorted order, not the kth distinct element.

Given a string s, find the first non-repeating character in it and return its index. If it does not exist, return -1.

Design and implement a data structure for Least Recently Used (LRU) cache. It should support get and put operations in O(1) time complexity.

Given the root of a binary tree, return the level order traversal of its nodes' values. (i.e., from left to right, level by level).

Given a string s, find the length of the longest substring without repeating characters.

Given an array of intervals where intervals[i] = [starti, endi], merge all overlapping intervals, and return an array of the non-overlapping intervals that cover all the intervals in the input.

Reverse a singly linked list. Provide both iterative and recursive solutions.

Given an array of integers nums and an integer target, return indices of the two numbers such that they add up to target. Assume exactly one solution exists.

Design a URL Shortening service like Bitly. Focus on the database schema and the URL generation algorithm.

How would you design a microservices architecture for an e-commerce checkout system? How do you handle inventory reservation?

Explain the Saga design pattern. How would you implement distributed transactions across multiple microservices?

How do you implement rate limiting for a public-facing API to prevent abuse?

Design a centralized logging and monitoring strategy for a distributed microservices application deployed on Kubernetes.

How do you handle service discovery and client-side load balancing in a Spring Boot microservices ecosystem?

Design an event-driven notification system using Apache Kafka. How do you ensure messages are not lost and are processed exactly once?

What is the difference between CompletableFuture and the standard Future interface in Java?

How does Spring Boot Auto-configuration work under the hood? Explain the role of @EnableAutoConfiguration.

How do you handle exceptions globally in a Spring Boot REST API?

Explain the different propagation behaviors available in Spring's @Transactional annotation. When would you use REQUIRES_NEW?

What is the difference between a clustered and a non-clustered index in a relational database?

Write a SQL query to find the second highest salary from an Employee table.

What is the difference between @Controller and @RestController in Spring Boot?

How does Garbage Collection work in Java? Can you explain the difference between the G1 Garbage Collector and the CMS Collector?

Explain the internal working of a ConcurrentHashMap in Java 8+. How does it differ from a synchronized HashMap?

Explain the concept of Dependency Injection (DI) and Inversion of Control (IoC). What are the benefits in an enterprise application?

How do you secure a REST API? Explain how JWT (JSON Web Tokens) work in a stateless authentication mechanism.

Explain the CAP theorem. How does it apply to a NoSQL database like Cassandra versus a relational database like PostgreSQL?

What is the N+1 select problem in Hibernate/JPA? How do you resolve it?

Describe a situation where you had to handle a Sev-1 production outage. What was your role, and how did you communicate with stakeholders during the incident?

Tell me about a time you experienced scope creep on a cloud migration or infrastructure project. How did you manage it while keeping the client satisfied?

Tell me about a time you had a technical disagreement with a senior engineer or architect on your team regarding a cloud design. How did you resolve it?

How do you explain complex cloud concepts, like containerization or serverless computing, to non-technical business stakeholders to justify project costs?

Tell me about a time you had to push back on a client's architectural request because it violated cloud best practices or security standards.

Write a Bash or Python script that integrates with the AWS CLI to find all IAM users who have not rotated their access keys in the last 90 days and outputs the list to a CSV.

Write a Python script using Boto3 (or equivalent Azure SDK) to find and delete all unattached EBS volumes older than 30 days to optimize cloud costs.

Write a Terraform module to provision a secure VPC baseline, including public/private subnets across two availability zones, a NAT Gateway, and appropriate Route Tables.

Write a bash or Python script to parse an Nginx or ALB access log file and output the top 10 IP addresses making requests.

Design a CI/CD pipeline for a containerized microservices application using GitLab CI or Jenkins, deploying to a Kubernetes cluster across Dev, QA, and Prod environments.

Design a Disaster Recovery (DR) strategy for a mission-critical financial application with a Recovery Point Objective (RPO) of 5 minutes and a Recovery Time Objective (RTO) of 1 hour.

A DXC enterprise client wants to migrate a legacy on-premise monolithic application to the cloud. Walk me through your migration strategy, from assessment to cutover.

Design a highly available hybrid cloud architecture connecting a client's on-premise data center to Azure, ensuring secure and low-latency data transfer.

How would you implement a Zero Trust architecture in a cloud environment for a highly regulated client?

Design a centralized logging and monitoring solution for a multi-cloud environment (AWS and Azure) that allows developers to trace requests across microservices.

Design an event-driven architecture using AWS Lambda, SQS, and SNS (or Azure equivalents) to process thousands of uploaded images asynchronously.

How do you protect a public-facing cloud application from Layer 7 DDoS attacks and SQL injection?

What is your strategy for upgrading a production Azure Kubernetes Service (AKS) or Amazon EKS cluster with minimal downtime?

A client's web application hosted on EC2 instances behind an Auto Scaling Group (ASG) is experiencing intermittent high latency. How do you troubleshoot this?

A client's AWS bill has spiked by 40% over the last quarter. As a Cloud Engineer, what steps would you take to identify the waste and optimize their costs?

Explain the Hub and Spoke network topology in Azure or AWS. Why is it preferred over a full-mesh VPC peering setup for large enterprises?

How do you handle secrets management (e.g., API keys, database passwords) in a CI/CD pipeline and within a Kubernetes environment?

You are paged because a critical microservice pod in an EKS/AKS cluster is stuck in a 'CrashLoopBackOff' state. Walk me through your exact troubleshooting steps.

In Kubernetes, what is the difference between a Deployment and a StatefulSet? Give a real-world enterprise use case for a StatefulSet.

How do you secure an AWS S3 bucket or Azure Blob Storage account from public access while ensuring a specific Virtual Network (VNet) or VPC can still access it?

A client wants to load balance traffic for a highly scalable web application and a backend database cluster. Explain the difference between an Application Load Balancer (ALB) and a Network Load Balancer (NLB), and when to use which.

How do you handle state file management and locking in Terraform when working with a distributed team of cloud engineers?

Explain the difference between Terraform and native IaC tools like Azure ARM templates or AWS CloudFormation. Why would a DXC enterprise client choose one over the other?

How do you manage IAM roles, policies, and security guardrails across hundreds of AWS accounts for a large enterprise client?

Explain the concept of an Azure Landing Zone or AWS Control Tower. Why is it a critical first step for DXC clients moving to the cloud?

What are 'cold starts' in serverless computing (e.g., AWS Lambda), and how do you mitigate them for latency-sensitive applications?

Compare Amazon RDS Multi-AZ deployments with Read Replicas. When would you recommend one over the other to a client?

A client needs to migrate a 5TB on-premise SQL Server database to Azure SQL Managed Instance with near-zero downtime. How do you achieve this?

How do you detect and manage configuration drift in an environment managed by Infrastructure as Code?

A client has a legacy Windows application (.NET Framework) that they want to modernize. How do you approach containerizing this application for the cloud?

Tell me about a time you had a disagreement with a client or stakeholder regarding technical requirements. How did you resolve it?

Describe your experience working in an Agile/Scrum environment with globally distributed teams.

How do you ensure data quality and governance in the pipelines you build?

Tell me about a time you failed to meet a project deadline. What happened and what did you learn?

Why do you want to work at DXC Technology as a Data Engineer?