This set of Data Structures & Algorithms Multiple Choice Questions & Answers (MCQs) focuses on “Quicksort
1. Which is the safest method to choose a pivot element?
A) choosing a random element as pivot
B) choosing the first element as pivot
C) choosing the last element as pivot
D) median-of-three partitioning method
Explanation: This is the best method for selecting the pivot element since a random pivot is unlikely to reliably produce a bad partition.
2. What is the average running time of a quick sort algorithm?
C) O(N log N)
D) O(log N)
Explanation: A quick sort algorithm’s best and average case analyses are found to be O mathematically (N log N).
3. Which of the following sorting algorithms is used along with quick sort to sort the sub arrays?
A) Merge sort
B) Shell sort
C) Insertion sort
D) Bubble sort
Explanation: The sub arrays are sorted using insertion sort and fast sort.
It is only seen at the very end.
4. Quick sort uses join operation rather than merge operation.
Explanation: Since join is a faster operation than merge, quick sort uses it.
5. How many sub arrays does the quick sort algorithm divide the entire array into?
Explanation: The entire array is split into two subarrays, the first of which contains elements less than the pivot element and the second of which contains elements greater than the pivot element.