Fundamentals of Data Structures Practice Questions
A-Levels · A-Level Computer Science · 146 free MCQs with instant results and detailed explanations.
146
Total
43
Easy
74
Medium
29
Hard
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Sample Questions from Fundamentals of Data Structures
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Q1
Easy
Which of the following is a characteristic of a stack data structure?
A.
Follows Last In First Out (LIFO) principle
B.
Allows random access of elements
C.
Uses a tree-like structure
D.
Follows First In First Out (FIFO) principle
Show Answer & Explanation
Correct Answer: A
A stack data structure follows the Last In First Out (LIFO) principle, meaning the last element added is the first to be removed.
Q2
Easy
In which scenario would it be most appropriate to use a queue data structure?
A.
Managing the order of tasks in a printer queue
B.
Storing history of web pages visited
C.
Implementing a recursive function
D.
Sorting a list of numbers
Show Answer & Explanation
Correct Answer: A
A queue is ideal for managing tasks in a printer queue because it follows the First In First Out (FIFO) principle, processing tasks in the order they were added.
Q3
Easy
Which of the following data structures uses the Last In First Out (LIFO) principle?
A.
Stack
B.
Queue
C.
Array
D.
Linked List
Show Answer & Explanation
Correct Answer: A
A stack is a data structure that follows the Last In First Out (LIFO) principle, meaning the last element added is the first one to be removed.
Q4
Medium
What is the primary characteristic of a linked list that differentiates it from an array?
A.
Elements are stored in contiguous memory locations.
B.
Elements can be easily inserted and deleted.
C.
Elements have a fixed size.
D.
Elements are accessed using an index.
Show Answer & Explanation
Correct Answer: B
A linked list allows for easy insertion and deletion of elements without reallocating the entire data structure, unlike an array which has fixed size and requires shifting elements.
Q5
Medium
In a binary search tree (BST), what property must all left child nodes satisfy?
A.
They must be greater than the parent node.
B.
They must be less than the parent node.
C.
They can be equal to the parent node.
D.
They must be greater than or equal to the right child.
Show Answer & Explanation
Correct Answer: B
In a binary search tree, all left child nodes must be less than their parent node to maintain the BST property, enabling efficient searching.
Q6
Medium
What is the time complexity of accessing an element in a hash table with good hash function and low collision rate?
A.
O(n)
B.
O(log n)
C.
O(1)
D.
O(n log n)
Show Answer & Explanation
Correct Answer: C
A well-designed hash table allows for average-case constant time complexity O(1) for access operations due to direct indexing via hash functions.
Q7
Medium
When implementing a stack using a linked list, what operation can be performed in constant time?
A.
Push an element onto the stack.
B.
Pop an element from the stack.
C.
Peek at the top element of the stack.
D.
All of the above.
Show Answer & Explanation
Correct Answer: D
In a stack implemented with a linked list, push, pop, and peek operations can all be performed in constant time O(1) because they involve manipulating only the head of the list.
Q8
Hard
In a binary search tree, what is the time complexity of searching for a value in the worst case scenario?
A.
O(log n)
B.
O(n)
C.
O(n log n)
D.
O(1)
Show Answer & Explanation
Correct Answer: B
In the worst case, a binary search tree can become unbalanced, resembling a linked list, leading to a time complexity of O(n) for searching a value.
Q9
Hard
Which of the following data structures would be the most efficient for implementing an LRU (Least Recently Used) cache?
A.
Array
B.
Doubly Linked List with a Hash Map
C.
Stack
D.
Queue
Show Answer & Explanation
Correct Answer: B
An LRU cache requires quick access and updating of the most recently used items. A doubly linked list allows for O(1) removal and addition, while a hash map provides O(1) access time, making this combination efficient.
Q10
Hard
Consider a binary search tree (BST) where the values of nodes are unique integers. If the root node has a value of 15, and its left child has a value of 10, what will be the value of the right child of the node with value 10 in an ideal BST?
A.
12
B.
10
C.
8
D.
9
Show Answer & Explanation
Correct Answer: D
In a binary search tree, the left child must have a value smaller than its parent, while the right child must have a value greater. Since 10 is less than 15, it can have a right child with a value between 10 and 15. The only plausible option that meets this condition is 9, which is greater than 8 and less than 10.
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Fundamentals of Data Structures — A-Levels A-Level Computer Science Practice Questions Online
This page contains 146 practice MCQs for the chapter Fundamentals of Data Structures in A-Levels A-Level Computer Science. The questions are organized by difficulty — 43 easy, 74 medium, 29 hard — so you can choose the right level for your preparation.
Every question includes a detailed explanation to help you understand the concept, not just memorize answers. Take a timed quiz to simulate exam conditions, or practice at your own pace with no time limit.