Engineering Questions with Answers - Multiple Choice Questions

# Heapsort MCQ’s – 1

1 - Question

On which algorithm is heap sort based on?
a) Fibonacci heap
b) Binary tree
c) Priority queue
d) FIFO

Explanation: Heap sort is based on the algorithm of priority queue and it gives the best sorting time.

2 - Question

In what time can a binary heap be built?
a) O(N)
b) O(N log N)
c) O(log N)
d) O(N2)

Explanation: The basic strategy is to build a binary heap of N elements which takes O(N) time.

3 - Question

Heap sort is faster than Shell sort.
a) true
b) false

Explanation: Heap sort is slower than Shell sort because Shell sort uses Sedgewick’s increment sequence.

4 - Question

Consider the following heap after buildheap phase. What will be its corresponding array? a) 26,53,41,97,58,59,31
b) 26,31,41,53,58,59,97
c) 26,41,53,97,31,58,59
d) 97,53,59,26,41,58,31

Explanation: Constructing a max heap using the elements 97,53,59,26,41,58,31 will cause the heap to look like that.

5 - Question

In what position does the array for heap sort contains data?
a) 0
b) 1
c) -1
d) anywhere in the array

Explanation: The array for heap sort contains data at position 0 whereas for a binary heap, array begins at 1. This is the reason for its complexity.

6 - Question

In heap sort, after deleting the last minimum element, the array will contain elements in?
a) increasing sorting order
b) decreasing sorting order
c) tree inorder
d) tree preorder

Explanation: By logic, after deleting minimum element, the heap will contain elements in decreasing sorting order. We can change this by altering the ordering property.

7 - Question

What is the typical running time of a heap sort algorithm?
a) O(N)
b) O(N log N)
c) O(log N)
d) O(N2)

Explanation: The total running time of a heap sort algorithm is mathematically found to be O(N log N).

8 - Question

How many arrays are required to perform deletion operation in a heap?
a) 1
b) 2
c) 3
d) 4

Explanation: To perform deletion operation in a heap, we require 2 arrays and that occupies extra memory space and hence increase in running time.

9 - Question

What is the time taken to perform a delete min operation?
a) O(N)
b) O(N log N)
c) O(log N)
d) O(N2)

Explanation: The time taken to perform a deletion of a minimum element is mathematically found to be O( log N).

10 - Question

Heap sort is an extremely stable algorithm.
a) true
b) false

Explanation: Heap sort uses fewer comparisons than other sorting algorithms and hence it is an extremely stable algorithm.

11 - Question

What is the average number of comparisons used in a heap sort algorithm?
a) N log N-O(N)
b) O(N log N)-O(N)
c) O(N log N)-1
d) 2N log N + O(N)

Explanation: The average number of comparisons in a heapsort algorithm is mathematically found to be 2N log N + O(N).

12 - Question

Explanation: The time taken to copy elements to and from the main array and extra array is found to be O(N). is the time taken to copy elements to and from two arrays created for deletion?
a) O(N)
b) O(N log N)
c) O(log N)
d) O(N2)

Explanation: The time taken to copy elements to and from the main array and extra array is found to be O(N).

13 - Question

What is the average number of comparisons used to heap sort a random permutation of N distinct items?
a) 2N log N-O(N)
b) 2N log N-O(N log N)
c) 2N log N-O(N log log N)
d) 2N log N-O(log N)