CS521 Midterm Preparation by ZB

Q1. Which data structure uses LIFO (Last In, First Out)?

1. Queue
2. Stack
3. Linked List
4. Tree

Answer: b) Stack

Q2. Which of the following is a disadvantage of an array?

1. Fast access to elements
2. Fixed size
3. Supports dynamic memory allocation
4. Simple to implement

Answer: b) Fixed size

Q3. In a binary search tree (BST), the left child of a node has a value that is:

1. Greater than the parent node
2. Smaller than the parent node
3. Equal to the parent node
4. None of the above

Answer: b) Smaller than the parent node

Q4. What is the time complexity of accessing an element in an array?

1. O(log n)
2. O(n)
3. O(1)
4. O(n log n)

Answer: c) O(1)

Q5. Which of the following is a stable sorting algorithm?

1. Quick Sort
2. Merge Sort
3. Heap Sort
4. Selection Sort

Answer: b) Merge Sort

Q6. Which algorithm is used for finding the shortest path in a weighted graph?

1. BFS
2. DFS
3. Dijkstra’s Algorithm
4. Kruskal’s Algorithm

Answer: c) Dijkstra’s Algorithm

Q7. Which of the following is not a characteristic of a queue?

1. FIFO (First In, First Out)
2. Operations are performed at the front and rear
3. Supports both insertions and deletions at any position
4. Used for scheduling processes

Answer: c) Supports both insertions and deletions at any position

Q8. What is the space complexity of an algorithm that uses constant space?

1. O(1)
2. O(n)
3. O(n^2)
4. O(log n)

Answer: a) O(1)

Q9. In a hash table, a collision occurs when:

1. Two keys map to the same index
2. Two keys are inserted into the table
3. The table exceeds its capacity
4. The table becomes empty

Answer: a) Two keys map to the same index

Q10. Which data structure is used in depth-first search (DFS)?

1. Queue
2. Stack
3. Array
4. Linked List

Answer: b) Stack

Q11. Which algorithm is used for graph traversal that visits all the nodes in a graph level by level?

1. Depth-First Search (DFS)
2. Dijkstra’s Algorithm
3. Bellman-Ford Algorithm
4. Breadth-First Search (BFS)

Answer: d) Breadth-First Search (BFS)

Q12. Which sorting algorithm has a worst-case time complexity of O(n^2)?

1. Merge Sort
2. Quick Sort
3. Selection Sort
4. Heap Sort

Answer: c) Selection Sort