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
31. What do you mean by overflow and underflow?
When new data is to be inserted into the data structure but there is no available space i.e. free storage list is empty this situation is called overflow.
When we want to delete data from a data structure that is empty this situation is called underflow.
32. What do you mean by recursive definition?
The definition which defines an object in terms of simpler cases of itself is called recursive definition.
33. What does abstract Data Type Mean?
That define the data type.
It is a useful tool for specifying the logical properties of a data type.
ADT consists of two parts
1) Values definition
2) Operation definition
Example:-The value definition for the ADT RATIONAL states that RATIONAL value consists of two integers, second does not equal to zero.
The operator definition for ADT RATIONAL includes the operation of creation (make rational) addition, multiplication and test for equality.
34. What is a linked list?
A linked list is a linear collection of data elements, called nodes, where the linear order is given by pointers. Each node has two parts first part contain the information of the element second part contains the address of the next node in the list.
35. What is a priority queue?
The priority queue is a data structure in which the intrinsic ordering of the elements (numeric or alphabetic)
Determines the result of its basic operation. It is of two types
36. What is a queue?
A queue is an ordered collection of items from which items may be deleted at one end (front end) and items inserted at the other end (rear end). It obeys FIFO rule there is no limit to the number of elements a queue contains.
37. What is a spanning Tree?
A spanning tree is a tree associated with a network. All the nodes of the graph appear on the tree once. A minimum spanning tree is a spanning tree organized so that the total edge weight between nodes is minimized.
38. What is dangling pointer and how to avoid it?
After a call to free(p) makes a subsequent reference to *p illegal, i.e. though the storage to p is freed but the value of p(address) remain unchanged .so the object at that address may be used as the value of *p (i.e. there is no way to detect the illegality).Here p is called dangling pointer.
To avoid this it is better to set p to NULL after executing free(p).The null pointer value does not reference a storage location it is a pointer that does not point to anything.
39. What is data structure?
The logical and mathematical model of a particular organization of data is called data structure. There are two types of data structure i) Linear ii) Nonlinear
40. What is sequential search?
Ans: In sequential search each item in the array is compared with the item being searched until a match occurs. It is applicable to a table organized either as an array or as a linked list.