Interview experience
NTT DATA Interview Questions and Answers (2026)
Real NTT DATA interview questions - candidate interview experiences and HR round prep, in one place.
Overview
Section titled “Overview”NTT DATA’s fresher process runs an AMCAT-style proctored written test, an optional GD, and a technical interview candidates consistently describe as noticeably harder than the earlier rounds.
NTT DATA interview process at a glance
Section titled “NTT DATA interview process at a glance”| Round | Duration | What they test |
|---|---|---|
| Online Written Test | Varies | Verbal, quant, logical reasoning, C/C++/OOPs/DBMS/OS/networks MCQs |
| Group Discussion (some campuses) | 15-20 min | Communication, structured thinking |
| Technical Interview | 30-45 min | Programming fundamentals, DSA, core CS, projects |
| HR Interview | Varies | Background, motivation, relocation flexibility |
Common technical interview questions and answers
Section titled “Common technical interview questions and answers”Q: What is the difference between a process and a thread?
A process is an independent program in execution with its own address space, file descriptors, and memory allocations, while a thread is a unit of execution inside a process that shares that address space, heap, and open files with sibling threads but keeps its own stack, registers, and program counter. Context switching between processes is expensive because it requires swapping page tables and flushing the TLB; switching between threads of the same process is much cheaper. The trade-off is isolation: a crash in one process cannot corrupt another, but one misbehaving thread can corrupt shared memory for the whole process, which is why threads need mutexes and other synchronisation.
Q: What is the difference between TCP and UDP?
TCP is connection-oriented: it performs a three-way handshake (SYN, SYN-ACK, ACK), numbers every byte, retransmits lost segments, reorders out-of-sequence data, and applies flow control through the receive window plus congestion control through slow start and congestion avoidance. UDP is connectionless with an eight-byte header, no handshake, no retransmission, and no ordering guarantee, so it is faster and has lower overhead. Use TCP where every byte must arrive - HTTP, SMTP, file transfer - and UDP where timeliness beats completeness, such as DNS queries, VoIP, live video, and online games.
Q: Explain the four pillars of OOP with an example.
Encapsulation binds data and the methods that operate on it into one unit and hides internal state behind private fields with public getters and setters, so a BankAccount class can reject a negative deposit. Abstraction exposes only what a caller needs through an interface or abstract class, hiding the implementation. Inheritance lets a SavingsAccount derive from Account and reuse its behaviour, modelling an is-a relationship. Polymorphism lets the same call resolve to different implementations - compile-time via method overloading, and runtime via method overriding through a base-class reference, which is what a virtual function table implements.
Q: Write a SQL query to find employees earning more than the average salary of their department.
Use a correlated subquery: SELECT e.name, e.dept_id, e.salary FROM Employee e WHERE e.salary > (SELECT AVG(salary) FROM Employee WHERE dept_id = e.dept_id). The inner query recomputes the average for each row’s department. A window-function version is usually faster because it makes one pass: SELECT name, dept_id, salary FROM (SELECT name, dept_id, salary, AVG(salary) OVER (PARTITION BY dept_id) AS avg_sal FROM Employee) t WHERE salary > avg_sal. Remember that AVG ignores NULL salaries in both forms.
Q: What is normalization, and what do 1NF, 2NF, and 3NF require?
Normalization organises tables to eliminate redundancy and update anomalies. 1NF requires atomic column values with no repeating groups or multi-valued fields. 2NF requires 1NF plus no partial dependency - every non-key attribute must depend on the whole composite primary key, not just part of it. 3NF requires 2NF plus no transitive dependency, so a non-key attribute must not depend on another non-key attribute. In practice teams often stop at 3NF or BCNF and then deliberately denormalize hot read paths, because each extra normal form adds joins that cost query performance.
Q: What is the difference between an array and a linked list?
An array stores elements in contiguous memory, so indexing is O(1) and cache locality is excellent, but insertion or deletion in the middle is O(n) because elements must shift, and resizing means allocating a new block and copying. A linked list stores nodes anywhere in memory with pointers, so inserting or deleting given a node reference is O(1), but access by index is O(n) and each node carries pointer overhead with poor cache behaviour. Choose an array for read-heavy indexed access and a linked list when you insert and remove frequently at known positions, such as inside an LRU cache.
Q: Compare merge sort and quicksort, including complexity and stability.
Merge sort divides the array in half, sorts each side recursively, then merges - guaranteed O(n log n) in all cases, stable, but needs O(n) auxiliary space. Quicksort partitions around a pivot and recurses on both sides, averaging O(n log n) with only O(log n) stack space and better constants in practice, but degrading to O(n squared) when pivots are consistently extreme, and it is not stable. Merge sort is preferred for linked lists, where merging needs no extra array, and for external sorting; quicksort is the usual in-memory default with randomised or median-of-three pivot selection.
Q: What is the difference between DELETE, TRUNCATE, and DROP in SQL?
DELETE is a DML statement that removes rows one at a time subject to a WHERE clause, fires triggers, logs each row, and can be rolled back. TRUNCATE is DDL: it deallocates the data pages for the whole table in one operation, is much faster, does not fire row triggers, and typically resets identity or auto-increment counters, but it cannot be filtered with WHERE. DROP is DDL that removes the table structure, its data, indexes, and constraints entirely. In most engines TRUNCATE and DROP cause an implicit commit, so treat them as irreversible in day-to-day work.
Frequently asked questions about NTT DATA interviews
Section titled “Frequently asked questions about NTT DATA interviews”What is the NTT DATA interview process like for freshers?
NTT DATA fresher hiring in India (Associate Software Engineer / Technical Graduate Trainee) usually runs 3-4 stages: 1. Online written test, frequently delivered on AMCAT or a similar proctored platform, covering verbal ability, quantitative ability, logical reasoning and computer programming, 2. A group discussion in some campus drives, 3. One or two technical interviews covering programming fundamentals, DSA, core CS subjects and your projects, and 4. An HR interview covering background, motivation and relocation flexibility. Candidate reports describe a timeline of roughly 2-4 weeks.
What questions are asked in the NTT DATA interview?
NTT DATA interviews commonly cover: Aptitude (quantitative, logical reasoning, verbal ability), Computer programming MCQs (C, C++, OOPs, DBMS, operating systems, computer networks and Unix basics), Coding and DSA (arrays, strings, sorting and searching, linked lists), Core CS discussion (OOPs concepts, SQL queries and joins, process vs thread, TCP vs UDP), Project discussion from your resume, and HR questions such as Why NTT DATA?, why an IT services career, and willingness to relocate across its India delivery locations.
How many rounds are there in the NTT DATA interview?
Most NTT DATA fresher drives run three main rounds - online written test, technical interview and HR interview. Some drives add a group discussion between the written test and the technical interview, making it four, and larger campuses sometimes split the technical stage into two interviews. Reports describe the written test and technical interview as the real elimination points, with HR being largely procedural once you clear the technical round in many drives.
What is the NTT DATA technical interview like?
The NTT DATA technical interview typically runs 30-45 minutes, often on a video call, and is reported to be noticeably harder than the earlier rounds. It covers: programming fundamentals in the language you list on your resume, data structures and algorithms with an emphasis on sorting, searching and basic array/string/linked-list problems, core CS subjects including DBMS and SQL, operating systems and computer networks, and a detailed walkthrough of your academic or internship projects. Explaining your approach and complexity clearly matters as much as reaching the optimal solution.