10 most commonly asked Data Structure Interview Questions

1. Where is data structure majorly used?

Simplistically speaking, data structures are involved in all areas when data is engaged. Some of the prominent areas where it is applied are artificial intelligence, database management, statistical analysis, etc.

2. Tell us about linked list.

A linked list can be defined as a chain of nodes wherein each node is connected to the next one.

3. What do you understand by data structure?

Data structure can ideally be defined as a data management, organization as well as storage format through which you can access as well as modify the data.
It is not only a collection of the values of data but defines the relationship with each other as well.

4. Tell us something about binary trees.

A binary tree is a form of data structure. It has two nodes, namely the left node and the right node.

5. What is a queue?

A queue is a form of data structure that induces a list of data. In this form of structure, the old elements are removed from one end while the new ones keep getting added to the other end.

6. What do you mean by LIFO?

LIFO stands for Last In First Out. It means that the data which was stored last would be the first one to be extracted.

7. What do you know about stack?

In stack, the newest data element is accessed first. As the name suggests, all old elements are pushed downwards leaving the last added one on the top.

8. Give us one advantage of linked list?

One inherent advantage of linked list is that it is very easy to modify irrespective of the number of elements that are there in the list.

9. What exactly do you mean by merge sort?

In merge sort, adjacent data elements are merged into one to form a bigger list. These lists are further merged into another big list and the process keeps happening until a single list is obtained.

10. What is the least number of nodes that a binary tree can have?

A binary tree can have zero nodes as the least number. Further, the number can be increased to 1 or 2 nodes.
Data structure is a large concept. A range of questions can be extracted from this data storage model. Keeping that in mind, we have another set of questions below that you should prepare for the interview.

• What do you understand by dynamic data structures?
• Tell us about arrays.
• Differentiate between Null and Void
• Cite the difference between Stack and Array.
• How would you define dequeue?
• Tell us about the working of a selection list.
• What do you know about graph?
• What exactly is an AVL tree?
• Do you know anything about Huffman’s algorithm?
• Tell us about recursive algorithm.

While appearing for your interview, present yourself gracefully and take time to figure out and plan the answers before you speak. In case you have any doubts about a question, ask the interviewer instead of beating around the bush.
Be confident and approach the day with an optimistic outlook. You are sure to crack the interview.

All the best!