Top MCQs on Sorting Algorithms with Answers

Question 11

The tightest lower bound on the number of comparisons, in the worst case, for comparison-based sorting is of the order of

• N
• N^2
• NlogN
• N(logN)^2

Question 12

In a modified merge sort, the input array is splitted at a position one-third of the length(N) of the array. Which of the following is the tightest upper bound on time complexity of this modified Merge Sort.

• N(logN base 3)

• N(logN base 2/3)

• N(logN base 1/3)

• N(logN base 3/2)

Question 13

Which sorting algorithm will take least time when all elements of input array are identical? Consider typical implementations of sorting algorithms.

• Insertion Sort

• Heap Sort

• Merge Sort

• Selection Sort

Question 14

In quick sort, for sorting n elements, the (n/4)th smallest element is selected as a pivot using an O(n) time algorithm. What is the worst-case time complexity of the quick sort?

(A) [Tex]\\theta [/Tex](n)

(B) [Tex]\\theta [/Tex](n*log(n))

(C) [Tex]\\theta [/Tex](n²)

(D) [Tex]\\theta [/Tex](n^{2 log n})

• A

• B

• C

• D

Question 15

Consider the Quicksort algorithm. Suppose there is a procedure for finding a pivot element that splits the list into two sub-lists each of which contains at least one-fifth of the elements. Let T(n) be the number of comparisons required to sort n elements. Then

• T(n) <= 2T(n/5) + n

• T(n) <= T(n/5) + T(4n/5) + n

• T(n) <= 2T(4n/5) + n

• T(n) <= 2T(n/2) + n

Question 16

Which of the following sorting algorithms has the lowest worst-case complexity?

• Merge Sort

• Bubble Sort

• Quick Sort

• Selection Sort

Question 17

Which sorting algorithms is most efficient to sort string consisting of ASCII characters?

• Quick sort
• Heap sort
• Merge sort
• Counting sort

Question 18

The number of elements that can be sorted in [Tex]\\Theta(logn)[/Tex] time using heap sort is

(A) [Tex]\\Theta(1)[/Tex]
(B) [Tex]\\Theta(\\sqrt{logn})[/Tex]
(C) [Tex]\\Theta(Log n/(Log Log n))[/Tex]
(d) [Tex]\\Theta(Log n)[/Tex] 

• A
• B
• C
• D

Question 19

Which of the following is true about merge sort?

• Merge Sort works better than quick sort if data is accessed from slow sequential memory.

• Merge Sort is stable sort by nature

• Merge sort outperforms heap sort in most of the practical situations.

• All of the above.

Question 20

Given an array where numbers are in range from 1 to n⁶, which sorting algorithm can be used to sort these number in linear time?

• Not possible to sort in linear time
• Radix Sort
• Counting Sort
• Quick Sort