Are there any worse sorting algorithms than Bogosort (a.k.a Monkey Sort)? [closed]

Answer 1

From David Morgan-Mar's Esoteric Algorithms page: Intelligent Design Sort

Introduction

Intelligent design sort is a sorting algorithm based on the theory of intelligent design.

Algorithm Description

The probability of the original input list being in the exact order it's in is 1/(n!). There is such a small likelihood of this that it's clearly absurd to say that this happened by chance, so it must have been consciously put in that order by an intelligent Sorter. Therefore it's safe to assume that it's already optimally Sorted in some way that transcends our naïve mortal understanding of "ascending order". Any attempt to change that order to conform to our own preconceptions would actually make it less sorted.

Analysis

This algorithm is constant in time, and sorts the list in-place, requiring no additional memory at all. In fact, it doesn't even require any of that suspicious technological computer stuff. Praise the Sorter!

Feedback

Gary Rogers writes:

Making the sort constant in time denies the power of The Sorter. The Sorter exists outside of time, thus the sort is timeless. To require time to validate the sort dimishes the role of the Sorter. Thus... this particular sort is flawed, and can not be attributed to 'The Sorter'.

Heresy!

Answer 2

Nothing can be worse than infinity.

Answer 3

Bozo sort is a related algorithm that checks if the list is sorted and, if not, swaps two items at random. It has the same best and worst case performances, but I would intuitively expect the average case to be longer than Bogosort. It's hard to find (or produce) any data on performance of this algorithm.

Answer 4

You could make any sort algorithm slower by running your "is it sorted" step randomly. Something like:

1. Create an array of booleans the same size as the array you're sorting. Set them all to false.
2. Run an iteration of bogosort
3. Pick two random elements.
4. If the two elements are sorted in relation to eachother (i < j && array[i] < array[j]), mark the indexes of both on the boolean array to true. Overwise, start over.
5. Check if all of the booleans in the array are true. If not, go back to 3.
6. Done.

Answer 5

Jingle Sort, as described here.

You give each value in your list to a different child on Christmas. Children, being awful human beings, will compare the value of their gifts and sort themselves accordingly.

Answer 6

One I was just working on involves picking two random points, and if they are in the wrong order, reversing the entire subrange between them. I found the algorithm on http://richardhartersworld.com/cri_d/cri/2001/badsort.html, which says that the average case is is probably somewhere around O(n^3) or O(n^2 log n) (he's not really sure).

I think it might be possible to do it more efficiently, because I think it might be possible to do the reversal operation in O(1) time.

Actually, I just realized that doing that would make the whole thing I say maybe because I just realized that the data structure I had in mind would put accessing the random elements at O(log n) and determining if it needs reversing at O(n).