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
71. What are the advantages of linked list over array (static data structure)?
The disadvantages of array are
i) unlike linked list it is expensive to insert and delete elements in the array
ii) One cant double or triple the size of array as it occupies block of memory space.
In linked list
i) each element in list contains a field, called a link or pointer which contains the address of the next element
ii) Successive elements need not occupy adjacent space in memory.
72. Can we apply binary search algorithm to a sorted linked list, why?
No we cannot apply binary search algorithm to a sorted linked list, since there is no way of indexing the middle element in the list. This is the drawback in using linked list as a data structure.
73. What do you mean by free pool?
Pool is a list consisting of unused memory cells which has its own pointer.
74. What do you mean by garbage collection?
It is a technique in which the operating system periodically collects all the deleted space onto the free storage list.
It takes place when there is minimum amount of space left in storage list or when CPU is ideal.
The alternate method to this is to immediately reinsert the space into free storage list which is time consuming.
75. 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.
76. What are the disadvantages array implementations of linked list?
i) The no of nodes needed cant be predicted when the program is written.
ii) The no of nodes declared must remain allocated throughout its execution
77. 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.
78. 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
i) Ascending priority queue- Here smallest item can be removed (insertion is arbitrary)
ii) Descending priority queue- Here largest item can be removed (insertion is arbitrary)
79. What are the disadvantages of sequential storage?
i) Fixed amount of storage remains allocated to the data structure even if it contains less element.
ii) No more than fixed amount of storage is allocated causing overflow
80. What are the disadvantages of representing a stack or queue by a linked list?
i) A node in a linked list (info and next field) occupies more storage than a corresponding element in an array.
ii) Additional time spent in managing the available list.