# Data Structure Interview Questions and Answers

## 1. What is Data Structure ?

**Answer :**Data structures are used to store data in a computer in an organized form...

## 2. If the depth of a tree is 3 levels, then what is the size of the Tree ?

A. 2

B. 4

C. 6

D. 8

**Answer : **D. 8

## 3. One of the following options is a form of access used to add and remove nodes from a queue ?

A. LIFO

B. FIFO

C. Both LIFO and FIFO

D. Recursion

**Answer : **B. FIFO

## 4. In case of the worst timing, which might be the worst to implement in sorting algorithm ?

A. Quick

B. Merge

C. Time

D. Heap

**Answer : **A. Quick

## 5. In regards to time complexity which will perform better ω(n^{4}) or O(n^{3}) ?

A. ω(n^{4})

B. O(n^{3})

C. Both Equally

D. Can't be said

**Answer : **A. ω(n^{4})

## 6. The time required to insert in the Queue is ?

A. O(n)

B. O(n^{2})

C. O(1)

D. O(log n)

**Answer : **C. O(1)

## 7. Which of the following has the quickest average time complexity ?

A. Quick

B. Radix

C. Bubble

D. Heap

**Answer : **B. Radix

## 8. Detect loop in a linked list ?

**Answer :**There are two ways to detect loop in linked list...

## 9. How to remove duplicates from a sorted linked list ?

**Answer :**To write a removeDuplicates() function which takes a list sorted...

## 10. Write a program to reverse a string using stack data structure ?

**Answer :**Given a string, reverse it using stack...

## 11. How to find Second largest element in a BST ?

**Answer :**In an N-ary tree, the second largest value in the given tree to find and return the node...

## 12. What is N Queen Problem ?

**Answer :**Let us discuss N Queen problem that can be solved using Backtracking...

## 13. Write a function to Delete a node from Doubly Linked List ?

**Answer :**In a single linked list, every node has link to its next node in the sequence...

## 14. What is Stack in Data Structure ?

**Answer :**A stack is a container of objects that are performed...

## 15. What is Queue in Data Structure ?

**Answer :**A queue is a container of objects (a linear collection) that are inserted...

## 16. Difference between Stack and Heap ?

**Answer :**Stack has very fast to access...

## 17. What is Linkedlist Data Structures with Example ?

**Answer :**A linked list is a sequence of data structures, which are connected...

## 18. What is Binary Tree in data structures ?

**Answer :**Binary tree is a special type of data structure...

## 19. How to detect a cycle in a linked list ?

**Answer :**A linked list is said to contain a cycle ...

## 20. How to delete an element in a linked list ?

**Answer :**To delete a node from linked list....

## 21. Write a function to get the intersection point of two Linked Lists ?

**Answer :**Intersection point means end of one linked list is linked..

## 22. Difference between Array and Linked List ?

**Answer :**Arrays are index-based data structure...

## 23. How to make a linked list program for a given list ?

**Answer :**Linked List is a type of Linear Data Structure that is mostly used data structure....

## 24. Inorder Tree Traversal without recursion and without stack ?

**Answer :**To traverse the tree using Morris Traversal...

## 25. Delete all occurrences of a given key in a linked list ?

**Answer :**Given a singly linked list, delete all occurrences...

## 26. What are the Minimum Initial Points to Reach Destination ?

**Answer :**To begin from the upper left corner of a given framework...

## 27. How to Count number of bits to be flipped to convert A to B ?

**Answer :**Write the program to count number of bits needed to be flipped...

## 28. How to Kadane's Algorithm is works ?

**Answer :**Given a 2D array, find the maximum sum subarray...

## 29. Find middle of Linked list ?

**Answer :**Given a singly linked list...

## 30. What is Binary search tree ?

**Answer :**The Binary search tree is a node-based on the binary tree data structure...