Top MCQs on MergeSort Algorithm with Answers

Question 1

A list of n string, each of length n, is sorted into lexicographic order using the merge-sort algorithm. The worst case running time of this computation is

• O (n*log(n))

• O (n² log n)

• O (n² + log(n))

• O (n²)

Question 2

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 3

If one uses straight two-way merge sort algorithm to sort the following elements in ascending order: 20, 47, 15, 8, 9, 4, 40, 30, 12, 17 then the order of these elements after second pass of the algorithm is:

• 8, 9, 15, 20, 47, 4, 12, 17, 30, 40
• 8, 15, 20, 47, 4, 9, 30, 40, 12, 17
• 15, 20, 47, 4, 8, 9, 12, 30, 40, 17
• 4, 8, 9, 15, 20, 47, 12, 17, 30, 40

Question 4

Given two sorted list of size m and n respectively. The number of comparisons needed the worst case by the merge sort algorithm will be

• m x n
• maximum of m and n
• minimum of m and n
• m + n - 1

Question 5

Of the following sorting algorithms, which has a running time that is least dependent on the initial ordering of the input?

• Merge Sort

• Insertion Sort

• Selection Sort

• Quick Sort

Question 6

You have to sort 1 GB of data with only 100 MB of available main memory. Which sorting technique will be most appropriate?

• Heap sort
• Merge sort
• Quick sort
• Insertion sort

Question 7

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 8

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 9

Assume that a mergesort algorithm in the worst case takes 30 seconds for an input of size 64. Which of the following most closely approximates the maximum input size of a problem that can be solved in 6 minutes?

• 256
• 512
• 1024
• 2048

Question 10

What is the best sorting algorithm to use for the elements in array are more than 1 million in general?

• Merge sort.
• Bubble sort.
• Quick sort.
• Insertion sort.