DATA STRUCTURES & ALGORITHMS EXAM LATEST 2026 UPDATE 100 QUESTIONS AND DETAILED VERIFIED ANSWERS FROM ACTUAL EXAMS TEST GRADE A+

DATA STRUCTURES & ALGORITHMS EXAM LATEST
2026 UPDATE 100 QUESTIONS AND DETAILED
VERIFIED ANSWERS FROM ACTUAL EXAMS TEST
GRADE A+

Questions 1–50
1. What data structure uses FIFO (First In First Out) principle?
A. Stack
B. Queue
C. Tree
D. Graph
Answer: B. Queue
Rationale: A queue processes elements in the order they arrive, following FIFO
behavior.


2. What is the time complexity of binary search?
A. O(n)
B. O(log n)
C. O(n²)
D. O(1)
Answer: B. O(log n)
Rationale: Binary search divides the search space in half each step.


3. Which data structure uses LIFO principle?
A. Queue
B. Stack
C. Array

,D. Linked List
Answer: B. Stack
Rationale: Stack processes last inserted element first.


4. Which traversal visits root, left, right?
A. Inorder
B. Postorder
C. Preorder
D. Level order
Answer: C. Preorder
Rationale: Preorder traversal follows root-left-right order.


5. Which data structure is best for recursion?
A. Queue
B. Stack
C. Heap
D. Graph
Answer: B. Stack
Rationale: Function calls are managed using a call stack.


6. Worst-case time complexity of linear search?
A. O(1)
B. O(log n)
C. O(n)
D. O(n²)
Answer: C. O(n)
Rationale: It may scan all elements.

, 7. Which sorting algorithm is fastest on average?
A. Bubble Sort
B. Quick Sort
C. Selection Sort
D. Insertion Sort
Answer: B. Quick Sort
Rationale: It has average O(n log n) performance.


8. Which data structure uses key-value pairs?
A. Array
B. Stack
C. Hash Table
D. Queue
Answer: C. Hash Table
Rationale: Hash tables map keys to values efficiently.


9. What is a linked list made of?
A. Nodes
B. Arrays
C. Trees
D. Graphs
Answer: A. Nodes
Rationale: Each node stores data and pointer.


10. Which traversal uses a queue?
A. DFS
B. BFS
C. Preorder
D. Postorder