The task was to extend or implement a small class design against stated behavior, not to optimize an algorithm. Some candidates get this as a two-part problem where the first part is a different bug-fix on the same log. The clean solution is a running open counter plus a separate complete counter, exactly the shape my own Question 2 used. Beyond my own two problems, candidates report a consistent set of question types on the Citi Karat SWE screen. Anything running on that screen, visible in the code editor, or reflected in how you type is fair game for the interviewer to notice. This is the part of the process most candidates underestimate.
The incident simulations carry authored Spark UI evidence (task tables, shuffle sizes, GC time) tuned to make the diagnostic signal clear, and the company on each question names the employer it was reported from. Thousands of tiny output files make every downstream read pay per-file listing and open overhead, and they bloat the metastore. DataFrame is a Dataset of Row with a schema, fully optimized, and the right default. RDD is the low-level distributed collection with no schema, so Catalyst cannot optimize it. Executor memory splits into an execution region (shuffles, joins, sorts) and a storage region (cached blocks), which borrow from each other, plus user memory and a fixed overhead. Cache() is persist() with the default MEMORY_AND_DISK storage level; persist() lets you name a different level.
Typing refers to type-checking in programming languages. What is the difference between ‘pop()’ and ‘remove()’ methods for lists? The next time the generator is called, it resumes from where it left off. It can be created using the ‘copy.deepcopy()’ function from the ‘copy’ module. The performance of the single-threaded process and the multi-threaded process will be the same in Python and this is because of GIL in Python.
- Compared with queues/pipes, shared memory offers Gb/s throughput for numeric arrays, essential in CV, RL, and zero-copy data loaders.
- Interviewers often expect senior candidates to mention these optimization techniques because they directly impact the scalability, reliability, and cost of Spark applications running in production.
- This allows for concurrent processing of requests, improving application performance.
- Are you ready to not just prepare, but truly transform your Python skills and confidently face the challenging interviews at leading companies like Accenture?
- To schedule scripts, on Linux and macOS you use cron, and on Windows you use Task Scheduler, this is used for daily backups, reports, or cleanup jobs, you just tell the system when to run your script, and it runs automatically without you opening it.
Add watermark-based deduplication so that late or replayed events within a 30-minute window are dropped. After a Kafka broker restart last week, the consumer group replayed 15 minutes of events, creating duplicate click counts in the output. Without broadcasting users (a downstream 2 GB enrichment step rules that out), spread that account’s rows across many tasks and return every account in users that has payments, with its payment count and total amount. Read the Spark UI evidence to find the root cause and fix the job so it meets SLA. She needs the same per-endpoint call totals from api_calls, produced in a way that stays small no matter how busy the hottest endpoint gets. Spark rounds converged on incidents because API questions stopped https://uvik.io/ separating candidates.
It lets you write scripts that drive Chromium, Firefox, and WebKit through a single API, which makes it the standard choice for cross-browser end-to-end testing in 2026. Useful whether you are a fresher prepping your first SDET interview, a Selenium or Cypress engineer making the switch, or a senior SDET going for a lead role. Recruiters want architecture, trade-offs, and a real debugging story, not just “I have written tests.” Embracing continuous learning and contributing to open-source projects can further enhance your skills and career prospects. Participation in Python community events, contributing to libraries on GitHub, or creating Python packages can enhance a developer’s resume.
Question 1: Bug-Fix on a Given Codebase
On the other hand, hiring managers can utilize this resource to assess candidates’ knowledge and competence during the interview process. Job seekers can use these questions to prepare for technical interviews and showcase their Python skills. How would you handle multicollinearity in a regression analysis using Python? Stack() is used to pivot the columns of a DataFrame to rows, while unstack() pivots the rows back to columns. Explain the purpose of the stack() and unstack() functions in Pandas with examples.
Now every test starts authenticated without running the login flow. Use newContext() whenever you need isolation, multiple users, different storage states, or different device emulations. Browser.newPage() opens a tab in a new, default context. Once you internalize this hierarchy, multi-user tests, storage state, and parallel isolation all start to make sense.
Here’s a quick overview of Cognizant’s interview process, difficulty level, and what candidates can expect throughout the hiring journey. The following resources cover the core computer science subjects commonly tested in Cognizant interviews. It delivers scalable, end-to-end technology solutions that improve operational efficiency, customer experience, and business agility across industries.
A Database Transaction is a set of database operations that must be treated as a whole, which means either all operations are executed or none of them. Polymorphism can be classified into two types based on the time when the call to the object or function is resolved. In simple terms, a constructor that creates an object by initializing it with an object of the same class, which has been created previously is known as a copy constructor. This insider’s perspective, armed with Virtusa Interview Questions you won’t find anywhere else, will empower you to confidently navigate the process and land your dream job at Virtusa. Aspiring for a challenging role at Virtusa? Virtusa provides domain expertise and technical skills to transform any business at a very large scale with good speed.