Data Structures and Algorithms – Multiple Choice Questions (MCQs)

1. 1. What is a linear data structure?

   • A. Tree
   • B. Graph
   • C. Array
   • D. Linked List

2. 2. Which data structure follows the Last-In, First-Out (LIFO) principle?

   • A. Queue
   • B. Stack
   • C. Tree
   • D. Graph

3. 3. Which data structure follows the First-In, First-Out (FIFO) principle?

   • A. Stack
   • B. Queue
   • C. Tree
   • D. Graph

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

   • A. O(1)
   • B. O(n)
   • C. O(log n)
   • D. O(n log n)

5. 5. What is the time complexity of searching for an element in an unsorted array?

   • A. O(1)
   • B. O(n)
   • C. O(log n)
   • D. O(n log n)

6. 6. What is the time complexity of searching for an element in a sorted array using binary search?

   • A. O(1)
   • B. O(n)
   • C. O(log n)
   • D. O(n log n)

7. 7. What is a linked list?

   • A. A contiguous block of memory
   • B. A collection of nodes where each node contains data and a pointer to the next node
   • C. A hierarchical data structure
   • D. A collection of key-value pairs

8. 8. What is the time complexity of inserting an element at the beginning of a singly linked list?

   • A. O(1)
   • B. O(n)
   • C. O(log n)
   • D. O(n log n)

9. 9. What is the time complexity of inserting an element at the beginning of a doubly linked list?

   • A. O(1)
   • B. O(n)
   • C. O(log n)
   • D. O(n log n)

10. 10. What is a stack?

    • A. A linear data structure that allows insertion and deletion at both ends
    • B. A linear data structure that allows insertion and deletion at one end only
    • C. A hierarchical data structure
    • D. A non-linear data structure

11. 11. The operation of adding an element to a stack is called:

    • A. Pop
    • B. Push
    • C. Peek
    • D. Enqueue

12. 12. The operation of removing an element from a stack is called:

    • A. Push
    • B. Pop
    • C. Peek
    • D. Dequeue