Top 51 Data Structures Interview Questions And Answers 2024

1. What is a Data Structure?

2. What are the resources of algorithm analysis?

3. What is the classification of data structure?

4. What do you mean by linear data structure?

5. What do you mean by non-linear data structure?

6. Write an algorithm to swap two variables?

7. What is the difference between the algorithm and flowchart?

8. What do you mean by pseudocode?

9. What do you mean by the complexity of the algorithms?

10. What is the complexity of an algorithm?

11. On what basis time complexity would be analysed?

12. What is an array?

13. What is the computational complexity of linear search?

14. What is Binary search?

15. How to read array input from user?

16. What do you mean by sorting?

17. What is a Linked list?

18. What is a doubly-linked list?

19. What is the difference between a singly linked list and an array?

20. What do you mean by a circular doubly linked list?

21. Write a traversing algorithm for the linked list?

22. What do you mean by memory allocation?

23. What do you mean by new and delete operator?

23. What do you mean by new and delete operator?

24. What is Stack in Data Structure ?

25. Write an algorithm for push operation of stack data structure?

26. Write an algorithm for pop operation?

27. What is a Queue in Data Structure ?

28. Write an algorithm for insertion in a queue?

29. Write an algorithm for deletion in a queue?

30. What do you mean by Dequeue?

31. Write an algorithm for bubble sort?

32. Write down the complexity of various sorting algorithms?

33. What do you mean by hashing?

34. What do you mean by the hash table?

35. What do you mean by hash function?

36. What do you mean by trees?

37. What do you mean by a binary tree?

38. What do you mean by binary search tree?

39. Explain traversing of a binary tree with example expression is :(p+q)*(4-3)

40. What do you mean by AVL Tree?

41. What do you mean by the graph?

42. What do you mean by a complete graph?

43. What do you mean by graph traversal techniques?

44. Define recursion?

45. Write down the vertices & edges in this graph?

46. What do you mean by linear search

47. What do you mean by AVL rotation?

48. Which data structure is used to perform recursion?

49. What do you mean by heap?

50. What do you mean by insertion sorting?

51. What do you mean by quick sort?

Data Structures Interview Questions And Answers

1. Data Structure:
   Ans. A data structure is a way of organizing and storing data to perform operations efficiently. It defines a set of operations that can be performed on the data and the properties of these operations. Common examples of data structures include arrays, linked lists, stacks, queues, trees, and graphs.
2. Resources of Algorithm Analysis:
   Ans.The resources of algorithm analysis are typically time and space. Time complexity measures the amount of time an algorithm takes to complete, while space complexity measures the amount of memory space it requires.
3. Classification of Data Structure:
   Ans.Data structures can be classified into two main types:

• Primitive Data Structures: These are the basic data structures that directly operate upon the machine instructions. Examples include integers, floats, characters, and pointers.
• Non-primitive Data Structures: These are more complex structures that are derived from primitive data structures. Examples include arrays, linked lists, stacks, queues, trees, and graphs.

4.Linear Data Structure:
Ans.A linear data structure is a structure in which elements are arranged in a linear or sequential order. Examples include arrays, linked lists, stacks, and queues.

5.Non-linear Data Structure:
Ans.A non-linear data structure is a structure in which elements are not arranged in a sequential order. Examples include trees and graphs.

6.Algorithm to Swap Two Variables:

Ans.

   Algorithm Swap(a, b):
      temp = a
      a = b
      b = temp

7. Difference between Algorithm and Flowchart:

Ans.

• Algorithm: It is a step-by-step procedure or set of rules to solve a specific problem.
• Flowchart: It is a visual representation of an algorithm that uses different shapes to represent different types of steps, decisions, and processes.

8.Pseudocode:

Ans.
Pseudocode is an informal way to express the logic of a computer program or algorithm. It uses a mixture of natural language and basic programming constructs to outline the structure of the algorithm.

9.Complexity of Algorithms:

Ans.
The complexity of an algorithm refers to the efficiency with which it uses resources. It is often measured in terms of time complexity and space complexity.

10.Basis for Time Complexity Analysis:
Ans. Time complexity is analyzed based on the growth rate of the algorithm’s running time concerning the input size. Common notations used are O (Big-O), Ω (Omega), and Θ (Theta).

11.Array:
Ans.An array is a collection of elements stored in contiguous memory locations and identified by an index or a key. The elements in an array are of the same data type.

12.Computational Complexity of Linear Search:
Ans.The worst-case time complexity of linear search is O(n), where ‘n’ is the number of elements in the array. It involves checking each element in the array until the target element is found.

13.Binary Search:
Ans.Binary search is an efficient algorithm for finding a target value within a sorted array. It works by repeatedly dividing the search interval in half.

Read Array Input from User: for i = 0 to length-1: input array[i]

14.Sorting:
Sorting is the process of arranging elements in a specific order, typically in ascending or descending order. Common sorting algorithms include bubble sort, insertion sort, selection sort, merge sort, and quicksort.

15.Linked List:
A linked list is a linear data structure in which elements are stored in nodes, and each node points to the next node in the sequence.

16.Doubly Linked List:
A doubly linked list is a linked list in which each node contains a data element and two pointers, one pointing to the next node and another pointing to the previous node in the sequence.

17.Difference between Singly Linked List and Array:

• In a singly linked list, elements are stored in nodes, and each node points to the next node. In an array, elements are stored in contiguous memory locations.
• The size of a singly linked list can be dynamic, while arrays have a fixed size.
• Accessing elements in an array is faster (constant time), while in a linked list, it may require traversing the list (linear time).