TCS interview questions and preparation
Prepare here for TCS NQT, Ninja, Digital, and Prime in one flow.
TCS most asked questions
Curated from repeated interview reports and prep guides so you can practice the prompts most likely to return.
Screening and technical
- How would you reverse the words in a string without using library shortcuts?
- Can you implement `atoi` or `strstr` and explain the edge cases?
- How do you check whether a string is a palindrome?
- What is the difference between a class and an interface?
- What is the difference between overloading and overriding?
- What is the difference between HTTP and HTTPS, and where does IPsec fit in network security?
Project and HR
- Explain your final-year project and your exact contribution.
- Which programming language are you most comfortable with and why?
- Why TCS, and which role fits you best: Ninja, Digital, or Prime?
- Can you speak on any topic for 2 minutes with a clear structure?
- Are you willing to relocate and work in shifts if the role needs it?
Coding bank
Focused on the coding patterns that keep repeating across TCS NQT, Digital, and CodeVita-style fresher preparation.
High-frequency bank
- Reverse a number or string, then explain the edge cases such as trailing zeros and negative input.
- Find the largest and second-largest element in an array without sorting unnecessarily.
- Rotate an array by K positions and explain the time-space tradeoff.
- Find the equilibrium index or symmetric pairs in an array-based problem.
- Count frequencies, remove duplicates, or move zeros while preserving useful order.
Stretch bank
- Practice TCS-style string-and-number hybrids such as String Pairs or vowel-count pair problems.
- Solve medium array simulation questions such as Card Shuffle or right-rotation variants.
- Prepare one longer CodeVita-style combinational problem such as Holes and Balls.
- Revise longest substring without repeating characters and similar sliding-window follow-ups.
- Keep one medium DP or greedy problem ready for Digital or Prime-level coding discussion.
TCS NQT Aptitude
TCS aptitude is usually direct, but time pressure makes it tricky.
Quantitative
- Percentage increase, train and platform, ratio, simple interest, profit and loss, time and work, and pipes and cistern.
- Revise number series, probability, and permutations like arranging APPLE.
Reasoning and Verbal
- Coding-decoding, blood relation, directions, circular seating, statement-conclusion, syllogism, and data sufficiency.
- Synonyms, error detection, fill in the blanks, para jumbles, and reading comprehension.
Coding Questions
TCS coding is usually based on arrays, strings, and numbers.
Most Asked Patterns
- Non-repeating element, rotate array by K, equilibrium index, second largest, remove duplicates, and move zeros to the end.
- Reverse number, palindrome, Fibonacci, prime, GCD or LCM, Armstrong, leap year, and reverse string.
PrepInsta-Style Problems
- Toggle bits after MSB, count Sundays in N days, and substring questions like maximizing one character.
TCS Ninja Interview
Ninja rounds usually mix direct technical questions with project and HR.
Technical and Core CS
- Array basics, DBMS, normalization, DELETE vs TRUNCATE, indexing, data warehouse, and OOPS concepts.
- Process vs thread, deadlock, scheduling, TCP/IP, and memory management.
Project and HR
- Explain your project, challenges, stack choice, and one future improvement.
- Prepare Tell me about yourself, Why TCS, Why should we hire you, relocation, and shift readiness.
TCS Digital
Digital expects stronger coding, SQL, APIs, and multithreading basics.
Technical and Coding
- JOIN queries, INNER vs LEFT JOIN, 3NF, multithreading, REST API, and hashing.
- Longest substring without repeating, dynamic programming starters, tree traversals, and optimized sorting discussion.
TCS Prime
Prime rounds move into advanced tech, design choices, and deeper project thinking.
Advanced Topics
- Machine learning, classifier types, reinforcement learning, LLMs, transformers, API design, and Git merge.
- System design of your project, scalability, database choice, and optimization.
Must-Do DSA
These are strong Digital or Prime revision targets.
High-Yield Problems
- Two Sum, Longest Substring Without Repeating, Merge Intervals, Binary Tree Level Order, LRU Cache, Kth Largest Element, and Detect Cycle in Linked List.