Data Structure MCQ

1. Which of the following data structures uses LIFO (Last In First Out) order?

• Queue

• Stack

• Linked List

• Array

2. Which of the following is a characteristic of a circular queue?

• It uses two pointers

• It allows insertion and deletion at both ends

• It has a fixed size

• The front and rear pointers can be equal when the queue is not full

3. Which of the following operations has a time complexity of O(1) in a hash table?

• Insertion

• Deletion
  

• Search

• All of the above

4. What is the time complexity of accessing an element in an array by its index?

• O(n)

• O(log n)

• O(1)

• O(n^2)

5. Which of the following data structures is used to implement recursion?

• Queue

• Stack

• Tree

• Graph

6. What is the worst-case time complexity for searching an element in a binary search tree (BST)?

• O(log n)

• O(n)

• O(n log n)

• O(1)

7. Which of the following is true about a doubly linked list?

• It allows traversal in only one direction
  

• Each node stores only data and a reference to the next node

• Each node stores references to both the previous and the next node

• It has no advantages over a singly linked list

8. Which of the following is not a type of tree traversal?

• Pre-order

• In-order

• Post-order

• Reverse-order

9. Which of the following operations is costly in a doubly linked list compared to a singly linked list?

• Insertion at the head

• Insertion at the tail

• Deletion of a node

• None of the above

10. In which scenario would a hash table be inefficient?

• When frequent insertions and deletions are required

• When keys are uniformly distributed

• When the data has a lot of collisions

• When quick lookups are needed