How many key comparisons does quick sort do if the array is already sorted how many element movements does it do?

Quicksort performs 39\% more comparisons than mergesort, but much less movement (copying) of array elements. We saw that, in the expected case, quicksort performs one exchange for every six comparisons, or about 1.39nlg(n)/6 ≈ 0.23nlg(n) exchanges.

How many comparisons are there in quicksort?

There are N/8 pairs of sets from #2 that are sorted with at most 7 comparisons each, for comparisons.

What is the problem with quick sort if the data is already sorted?

By choosing the first element of the array as the pivot, you hit the quicksort worst-case behavior when the array is already sorted. So you get O(n2) behavior (and worse, O(n) stack space, which probably gives you a stack overflow).

How many number of comparisons are required in insertion sort to sort a file if the file is sorted in reverse order?

Part (a) of Figure 5.15 shows that 10 comparisons are required to sort the five items when they are originally arranged in reverse sorted order.

How many comparisons does selection sort make?

In general, the average number of comparisons per pass in selection sort will always be one half of the number of items to be sorted. For eight items, we have 1/2(82 + 8) = 1/2(64 + 8) = 1/2(72) = 36 comparisons.

How many sub arrays does the quick sort algorithm divide the entire array into?

How many sub arrays does the quick sort algorithm divide the entire array into? Explanation: The entire array is divided into two partitions, 1st sub array containing elements less than the pivot element and 2nd sub array containing elements greater than the pivot element. 11.

How do you find the number of comparisons in sorting?

How do you count the number of comparisons in heap sort?

Heap sort makes at most 1.5*N calls on downHeap. DownHeap makes at most log(N) iterations, and each iteration makes two comparisons, so heap sort makes at most 3*N*log(N) comparisons. It can be shown than bottom up heap sort actually makes at most 2*N*log(N) comparisons.

What will be the complexity of quicksort If list contains element?

The runtime complexity is expected to be O(n log n) as the selected random pivots are supposed to avoid the worst case behavior.

Why is quicksort faster than mergesort?

Auxiliary Space : Mergesort uses extra space, quicksort requires little space and exhibits good cache locality. Merge sort requires a temporary array to merge the sorted arrays and hence it is not in-place giving Quick sort the advantage of space.