quicksort

The quicksort algorithm has an average time complexity of O(n*log(n)) and a worst case complexity of O(n^2). Assuming some variant of Hoare’s quicksort algorithm, what kinds of input will cause the quicksort algorithm to exhibit worst case complexity? Please state any assumptions relating to implementation details regarding the specific quicksort algorithm such as pivot selection, etc. or if it's sourced from a commonly available library such as libc. Some reading: A Killer Adversary for Quicksort Quicksort Is Optimal Engineering a Sort Function Introspective Sorting and Selection Algorithms

In Introduction to Algorithms p169 it talks about using tail recursion for Quicksort . The original Quicksort algorithm earlier in the chapter is (in pseudo-code) Quicksort(A, p, r) { if (p < r) { q: <- Partition(A, p, r) Quicksort(A, p, q) Quicksort(A, q+1, r) } } The optimized version using tail recursion is as follows Quicksort(A, p, r) { while (p < r) { q: <- Partition(A, p, r) Quicksort(A, p, q) p: <- q+1 } } Where Partition sorts the array according to a pivot. The difference is that the second algorithm only calls Quicksort once to sort the LHS. Can someone explain to me why the 1st

I have a problem with how the List Sort method deals with sorting. Given the following element: class Element : IComparable<Element> { public int Priority { get; set; } public string Description { get; set; } public int CompareTo(Element other) { return Priority.CompareTo(other.Priority); } } If I try to sort it this way: List<Element> elements = new List<Element>() { new Element() { Priority = 1, Description = "First" }, new Element() { Priority = 1, Description = "Second" }, new Element() { Priority = 2, Description = "Third" } }; elements.Sort(); Then the first element is the previously

I am working on implementing a quicksort function to sort singly linked lists. What algorithm would I have to use to accomplish this ? For a linked list it would take worst case O(N) for each comparison, instead of the usual O(1) for arrays. So what would the worst case complexity be ? To sum up, what modifications do I need to make to the quicksort algorithm to have an optimal sorting algorithm and what would be the worst case complexity of the algorithm ? Thanks! I have an implementation below: public static SingleLinkedList quickSort(SingleLinkedList list, SLNode first, SLNode last) { if

I've never seen dual pivot quick sort before. If it is a upgrade edition of quick sort? And what is the difference of dual pivot quick sort and quick sort? Brutal_JL I find this in the Java doc. The sorting algorithm is a Dual-Pivot Quicksort by Vladimir Yaroslavskiy, Jon Bentley, and Joshua Bloch. This algorithm offers O(n log(n)) performance on many data sets that cause other quicksorts to degrade to quadratic performance, and is typically faster than traditional (one-pivot) Quicksort implementations. Then I find this in the Google search result. Thoery of quick sort algorithm: Pick an

I know that quicksort has O(n log n) average time complexity. A pseudo-quicksort (which is only a quicksort when you look at it from far enough away, with a suitably high level of abstraction) that is often used to demonstrate the conciseness of functional languages is as follows (given in Haskell): quicksort :: Ord a => [a] -> [a] quicksort [] = [] quicksort (p:xs) = quicksort [y | y<-xs, y<p] ++ [p] ++ quicksort [y | y<-xs, y>=p] Okay, so I know this thing has problems. The biggest problem with this is that it does not sort in place, which is normally a big advantage of quicksort. Even if