15 extra multiple-choice questions for Algorithmic Strategies (12th Standard Computer Science, Samacheer Kalvi), beyond the ones printed in the textbook — each with the correct option highlighted and a clear, worked explanation. Free to read in English and Tamil.
Q1
Which phase of algorithmic analysis represents a theoretical performance analysis where the efficiency is measured by assuming external factors?
- A. A Posteriori testing
- B. A Priori estimatesCorrect
- C. Asymptotic notation
- D. System testing
Explanation. A Priori estimates is the theoretical analysis of an algorithm's performance where efficiency is calculated under assumed external factors, whereas A Posteriori testing involves actual performance measurement during execution.
Q2
In space complexity, which component represents the total space required by variables whose size depends on the problem size and recursion?
- A. Fixed part
- B. Static part
- C. Variable partCorrect
- D. Auxiliary part
Explanation. The space complexity of an algorithm consists of a fixed part for constants and simple variables, and a variable part for recursion and variables whose size depends on the problem size.
Q3
Which asymptotic notation is used to describe the lower bound or the best-case scenario of an algorithm?
- A. Big O
- B. Big Theta
- C. Big OmegaCorrect
- D. Big o
Explanation. Big Omega represents the lower bound of an asymptotic function, which is used to describe the best-case execution time of an algorithm.
Q4
If a sequential search is performed on a list of n elements, what is the mathematical formula used to calculate the average number of comparisons?
- A. n / 2
- B. (n + 1) / 2Correct
- C. n * (n - 1) / 2
- D. (n - 1) / 2
Explanation. The average number of comparisons in linear search is calculated as the sum of the minimum comparison and maximum comparisons, divided by 2, resulting in (n + 1)/2.
Q5
What is defined as the specific way of designing an algorithm to solve a given problem?
- A. Algorithmic strategyCorrect
- B. Algorithmic solution
- C. Program statement
- D. Subroutine design
Explanation. An algorithmic strategy is the way of defining an algorithm, such as using recursive functions or iterative loops to solve a particular problem logically.
Q6
What is the primary prerequisite or condition that must be met by a list of elements before performing a Binary Search?
- A. The list must be unsorted.
- B. The list must be sorted.Correct
- C. The list must contain only integers.
- D. The list must have an even number of elements.
Explanation. For binary search to function correctly, the elements in the array must be sorted beforehand so that the divide-and-conquer strategy can be applied based on the middle value.
Q7
Why is the Bubble Sort algorithm considered less efficient when compared to other methods like Insertion Sort?
- A. It does not use adjacent comparisons.
- B. It is too slow because it repeatedly compares adjacent elements and performs many swaps.Correct
- C. It requires a sorted array as input.
- D. It cannot handle string arrays.
Explanation. Although simple, Bubble Sort is slow and less efficient for large datasets because it continuously compares adjacent elements and performs multiple swaps in successive passes.
Q8
Which sorting algorithm improves on the performance of bubble sort by making only a single swap or exchange for every pass through the list?
- A. Insertion sort
- B. Quick sort
- C. Selection sortCorrect
- D. Merge sort
Explanation. Selection sort improves on Bubble Sort by finding the minimum element in each pass and performing only one exchange per pass, thus minimizing the total number of swaps.
Q9
How does the Insertion Sort algorithm build its final sorted array?
- A. By swapping the largest elements to the end of the array
- B. By dividing the array in half and sorting each recursively
- C. By taking elements one by one and inserting them in their correct position in a sorted sub-listCorrect
- D. By randomly distributing elements into buckets
Explanation. Insertion Sort builds the final sorted list one item at a time by taking an element and placing it into its appropriate position within the already sorted sub-list.
Q10
Dynamic programming divides a problem into smaller sub-problems. Which key optimization technique does it use to speed up execution by storing the results of previous function calls?
- A. Recursing
- B. Backtracking
- C. MemoizationCorrect
- D. Parsing
Explanation. Memoization is an optimization technique used in dynamic programming that caches the results of expensive function calls to avoid redundant computations when the same inputs occur again.
Q11
In Bubble Sort, what is guaranteed about the position of elements after the completion of the first iteration (iteration-1)?
- A. The smallest element bubbles up to the first position.
- B. The entire array is fully sorted.
- C. The largest element is placed at its correct final position at the end of the array.Correct
- D. The middle element is moved to the center.
Explanation. During the first iteration of Bubble Sort, the largest element repeatedly swaps with adjacent elements until it bubbles down to the very end of the array, securing its final sorted position.
Q12
Which of the following represents the correct formula used in pseudo-code to calculate the middle index of an array in Binary Search?
- A. mid = low + high / 2
- B. mid = low + (high - low) / 2Correct
- C. mid = (high - low) / 2
- D. mid = low - (high + low) / 2
Explanation. The middle index in binary search is calculated using the formula mid = low + (high - low) / 2 to find the exact midpoint and prevent integer overflow issues in large arrays.
Q13
What does the term space-time tradeoff refer to in algorithm design?
- A. Minimizing both space and execution time simultaneously
- B. Designing an algorithm that works only on standard platforms
- C. Solving a problem in less time by using more memory, or vice versaCorrect
- D. The physical time taken to clear the RAM after execution
Explanation. Space-time tradeoff is a design paradigm where an algorithm's execution speed is increased at the cost of consuming more memory, or memory usage is minimized by increasing runtime.
Q14
According to the characteristics of an algorithm, what does the term Unambiguous mean?
- A. The algorithm must have zero inputs.
- B. Each step and its inputs/outputs must be clear and lead to only one meaning.Correct
- C. The algorithm should be generic and independent of any programming language.
- D. The algorithm must terminate after a finite number of steps.
Explanation. Unambiguous specifies that every step of an algorithm, as well as its inputs and outputs, must be completely clear and not open to multiple interpretations.
Q15
Which characteristic of an algorithm ensures that it must terminate or stop after a specific number of steps?
- A. Feasibility
- B. Definiteness
- C. FinitenessCorrect
- D. Correctness
Explanation. Finiteness requires that an algorithm must have a limit and must terminate after executing a finite number of steps, rather than running in an infinite loop.
Frequently asked questions
How many MCQs are there in Algorithmic Strategies?
This chapter has 15 book-back multiple-choice questions, each with the correct answer and a step-by-step explanation.
Are these 12th Standard Computer Science MCQs free to practise online?
Yes. Every question, answer and explanation here is free, and you can also take them as a timed practice test.
Where can I find the Algorithmic Strategies book-back answers?
The correct option for each question is highlighted on this page with a worked explanation, plus a quick answer-key summary at the top.
