Technical interview questions and answers are the foundation of any Data Structure Interview because companies use DSA to test your problem-solving ability, logic building, and coding efficiency. Data Structures such as arrays, linked lists, stacks, queues, trees, and graphs form the backbone of programming, making this topic one of the most important parts of technical rounds. In campus placements and company-specific interviews conducted by TCS, Infosys, Wipro, Cognizant, and Capgemini, these questions decide whether a candidate has strong fundamentals. This guide covers the most important and frequently asked Data Structure interview questions with clear explanations, helping freshers and job seekers understand concepts easily. Preparing these questions improves performance in coding tests, whiteboard interviews, and online assessments.
Computer science professionals should complement their algorithmic knowledge with C language implementation and Java programming techniques
Showing 10 of 108 questions
41. What is the data structures used to perform recursion?
Stack. Because of its LIFO (Last In First Out) property it remembers its 'caller' so knows whom to return when the function has to return. Recursion makes use of system stack for storing the return addresses of the function calls. Every recursive function has its equivalent iterative (non-recursive) function. Even when such equivalent iterative procedures are written, explicit stack is to be used.
42. What is the difference between a Stack and an Array?
i) Stack is a ordered collection of items
ii) Stack is a dynamic object whose size is constantly changing as items are pushed and popped .
iii) Stack may contain different data types
iv) Stack is declared as a structure containing an array to hold the element of the stack, and an integer to indicate the current stack top within the array.
ARRAY
i) Array is an ordered collection of items
ii) Array is a static object i.e. no of item is fixed and is assigned by the declaration of the array
iii) It contains same data types.
iv) Array can be home of a stack i.e. array can be declared large enough for maximum size of the stack.
43. What is the type of the algorithm used in solving the 8 Queens problem?
Backtracking
44. Whether Linked List is linear or Non-linear data structure?
According to Storage Linked List is a Non-linear one.
45. If you are using C language to implement the heterogeneous linked list, what pointer
type will you use?
The heterogeneous linked list contains different data types in its nodes and we
need a link, pointer to connect them. It is not possible to use ordinary pointers for this. So
we go for void pointer. Void pointer is capable of storing pointer to any type as it is a
generic pointer type.
46. Minimum number of queues needed to implement the priority queue?
Two. One queue is used for actual storing of data and another for storing
priorities.
47. What is the data structures used to perform recursion?
Stack. Because of its LIFO (Last In First Out) property it remembers its ‘caller so knows whom to return when the function has to return. Recursion makes use of system stack for storing the return addresses of the function calls.
Every recursive function has its equivalent iterative (non-recursive) function. Even when such equivalent iterative procedures are written, explicit stack is to be used.
48. What are the notations used in Evaluation of Arithmetic Expressions using prefix and
postfix forms?
Polish and Reverse Polish notations.
49. Sorting is not possible by using which of the following methods?
(a) Insertion
(b) Selection
(c) Exchange
(d) Deletion
(d) Deletion.
Using insertion we can perform insertion sort, using selection we can perform
selection sort, using exchange we can perform the bubble sort (and other similar sorting
methods). But no sorting method can be done just using deletion.
50. What are the methods available in storing sequential files ?
Straight merging,
Natural merging,
Polyphase sort,
Distribution of Initial runs.