Fundamentals of Algorithms Practice Questions
A-Levels · A-Level Computer Science · 145 free MCQs with instant results and detailed explanations.
145
Total
46
Easy
74
Medium
25
Hard
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Sample Questions from Fundamentals of Algorithms
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Q1
Easy
What is the primary purpose of an algorithm in computer science?
A.
To solve a specific problem
B.
To write a computer program
C.
To design a graphical user interface
D.
To manage system memory
Show Answer & Explanation
Correct Answer: A
An algorithm is a step-by-step procedure or formula for solving a problem, making its primary purpose to provide a solution.
Q2
Easy
In which case would a bubble sort algorithm be preferred over other sorting algorithms?
A.
When sorting large datasets
B.
When the dataset is small and simplicity is desired
C.
When the dataset contains unique elements only
D.
When the sorting time must be minimized
Show Answer & Explanation
Correct Answer: B
Bubble sort is most efficient for small datasets due to its simplicity and ease of implementation, despite not being optimal for larger sets.
Q3
Easy
What does 'Big O notation' primarily describe?
A.
The speed of an algorithm
B.
The memory usage of an algorithm
C.
The efficiency of an algorithm in terms of time complexity
D.
The number of lines in an algorithm
Show Answer & Explanation
Correct Answer: C
Big O notation is used to classify algorithms according to how their run time or space requirements grow as the input size grows, specifically focusing on time complexity.
Q4
Medium
Which of the following best describes a linear search algorithm?
A.
It divides the data into halves recursively to find an element.
B.
It checks each element in a list sequentially until the desired element is found.
C.
It uses a hash function to find the index of the desired element directly.
D.
It employs a tree structure to organize the data for faster searches.
Show Answer & Explanation
Correct Answer: B
A linear search algorithm checks each element one by one in the list until it finds the target element or reaches the end, making option B correct.
Q5
Medium
What is the time complexity of the bubble sort algorithm in the worst case?
A.
O(n log n)
B.
O(n^2)
C.
O(n)
D.
O(1)
Show Answer & Explanation
Correct Answer: B
The worst-case time complexity for bubble sort occurs when the array is sorted in reverse order, requiring n(n-1)/2 comparisons, which simplifies to O(n^2), making option B correct.
Q6
Medium
In a recursive function, what is the purpose of the base case?
A.
To ensure the function continues indefinitely.
B.
To provide a stopping condition for the recursion.
C.
To define the maximum depth of recursion allowed.
D.
To optimize the recursion process for performance.
Show Answer & Explanation
Correct Answer: B
The base case is crucial in recursion as it provides a stopping condition that prevents infinite recursion by defining when the function should return a value, making option B correct.
Q7
Medium
Which algorithm is best suited for finding the shortest path in a weighted graph?
A.
Quick Sort
B.
Dijkstra's Algorithm
C.
Binary Search
D.
Merge Sort
Show Answer & Explanation
Correct Answer: B
Dijkstra's Algorithm is specifically designed for finding the shortest paths from a source vertex to all other vertices in a weighted graph, making option B the correct choice.
Q8
Hard
What is the time complexity of the binary search algorithm 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: A
Binary search works by dividing the search interval in half repeatedly. In the worst case, it will take log(n) comparisons to find the target value, leading to a time complexity of O(log n).
Q9
Hard
Consider a sorting algorithm that processes n elements and performs O(n^2) comparisons in the worst-case scenario. Which of the following sorting algorithms is most likely to exhibit this performance?
A.
Quick Sort
B.
Bubble Sort
C.
Merge Sort
D.
Heap Sort
Show Answer & Explanation
Correct Answer: B
Bubble Sort is a simple sorting algorithm that compares each pair of adjacent elements and swaps them if they are in the wrong order. In the worst-case scenario, it will perform O(n^2) comparisons when the list is sorted in reverse order.
Q10
Hard
In a binary search algorithm, what is the worst-case time complexity for searching an element in a sorted array of n elements?
A.
O(log n)
B.
O(n)
C.
O(n log n)
D.
O(1)
Show Answer & Explanation
Correct Answer: A
The binary search algorithm divides the array in half at each step, leading to a logarithmic time complexity in the worst case. Therefore, the time complexity is O(log n).
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Fundamentals of Algorithms — A-Levels A-Level Computer Science Practice Questions Online
This page contains 145 practice MCQs for the chapter Fundamentals of Algorithms in A-Levels A-Level Computer Science. The questions are organized by difficulty — 46 easy, 74 medium, 25 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.