If a quicksort implementation uses the first element in each subproblem as the pivot, which of the following scenarios results in the worst-case runtime?1 PointGrading comment:Choice 1 of 4:The input list is already sorted but in reverseChoice 2 of 4:The input list is already sortedChoice 3 of 4:The input list is randomly shuffledChoice 4 of 4:The input list contains more than 2000 elements
Question
If a quicksort implementation uses the first element in each subproblem as the pivot, which of the following scenarios results in the worst-case runtime?1 PointGrading comment:Choice 1 of 4:The input list is already sorted but in reverseChoice 2 of 4:The input list is already sortedChoice 3 of 4:The input list is randomly shuffledChoice 4 of 4:The input list contains more than 2000 elements
Solution
The worst-case runtime for a quicksort implementation that uses the first element in each subproblem as the pivot occurs when:
Choice 1 of 4: The input list is already sorted but in reverse
Explanation: Quicksort's worst-case scenario occurs when the pivot is the smallest or largest element in the list, causing an unbalanced partition where one partition contains n-1 elements and the other contains 0 elements. This results in a worst-case time complexity of O(n^2). If the list is already sorted in reverse and the first element is chosen as the pivot, this worst-case scenario will occur.
Similar Questions
L = [20, 9, 25, 41, 3, 4, 34, 6, 23]1.Which of the following is the correct ordering for L after a single in-place run through of `quicksort` (just before the recursive call is made), using the final element as pivot ?
The running time of quick sort depends heavily on the selection of Select one:Pivot elementNo of inputs Arrangement of elements in array Size of elements
The O(n log n) average-case running time analysis of quicksort relies on several assumptions. Which of the following does not need to be assumed:Group of answer choicesThat each function call can be carried out in O(1) timeThat each comparison of two elements can be carried out in O(1) timeThat the result of each partitioning step is an arrangement in which the pivot value is equally likely to end up in each position of the partitioned arrayThat the result of each partitioning step is an arrangement in which the pivot value ends up close to the middle of the partitioned arrayThat each swap of two elements can be carried out in O(1) time
What is the time complexity of the quicksort algorithm in the worst case?
What is recurrence for worst case of QuickSort and what is the time complexity in Worst case?
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