BogoSort

In computer science, bogosort (also known as permutation sort and stupid sort) is a sorting algorithm based on the generate and test paradigm. The function successively generates permutations of its input until it finds one that is sorted. It is not considered useful for sorting, but may be used for educational purposes, to contrast it with more efficient algorithms. The algorithm's name is a portmanteau of the words ''bogus'' and ''sort''.

Two versions of this algorithm exist: a deterministic version that enumerates all permutations until it hits a sorted one,. and a randomized version that randomly permutes its input and checks whether it is sorted. An analogy for the working of the latter version is to sort a deck of cards by throwing the deck into the air, picking the cards up at random, and repeating the process until the deck is sorted. In a worst-case scenario with this version, the random source is of low quality and happens to make the sorted permutation unlikely to occur.

Description of the algorithm

Pseudocode

The following is a description of the randomized algorithm in pseudocode:

while deck is not sorted:
shuffle(deck)

C

An implementation in C:
#include
#include
#include

// executes in-place bogo sort on a given array
static void bogo_sort(int* a, int size);
// returns 1 if given array is sorted and 0 otherwise
static int is_sorted(int* a, int size);
// shuffles the given array into a random order
static void shuffle(int* a, int size);

void bogo_sort(int* a, int size)

int is_sorted(int* a, int size)

void shuffle(int* a, int size)

int main()

Python

An implementation in Python:

import random

# this function checks whether or not the array is sorted
def is_sorted(random_array):
for i in range(1, len(random_array)):
if random_array < random_array - 1
return False
return True

# this function repeatedly shuffles the elements of the array until they are sorted
def bogo_sort(random_array):
while not is_sorted(random_array):
random.shuffle(random_array)
return random_array

# this function generates an array with randomly chosen integer values
def generate_random_array(size, min_val, max_val):
return andom.randint(min_val, max_val) for _ in range(size)

# the size, minimum value and maximum value of the randomly generated array
size = 10
min_val = 1
max_val = 100
random_array = generate_random_array(size, min_val, max_val)
print("Unsorted array:", random_array)
sorted_arr = bogo_sort(random_array)
print("Sorted array:", sorted_arr)

This code creates a random array - random_array - in generate_random_array that would be sorted by shuffling it in bogosort. All data in the array is natural numbers from 1 - 100.

Running time and termination

If all elements to be sorted are distinct, the expected number of comparisons performed in the average case by randomized bogosort is asymptotically equivalent to , and the expected number of swaps in the average case equals .. The expected number of swaps grows faster than the expected number of comparisons, because if the elements are not in order, this will usually be discovered after only a few comparisons, no matter how many elements there are; but the work of shuffling the collection is proportional to its size. In the worst case, the number of comparisons and swaps are both unbounded, for the same reason that a tossed coin might turn up heads any number of times in a row.

The best case occurs if the list as given is already sorted; in this case the expected number of comparisons is , and no swaps at all are carried out.

For any collection of fixed size, the expected running time of the algorithm is finite for much the same reason that the infinite monkey theorem holds: there is some probability of getting the right permutation, so given an unbounded number of tries it will almost surely eventually be chosen.

Related algorithms

See also

* Las Vegas algorithm
* Stooge sort

References

External links

* BogoSort on WikiWikiWeb

Inefficient sort algorithms

Bogosort
an implementation that runs on Unix-like systems, similar to the standard sort program.

Bogosort
an
jmmcg::bogosort
Simple, yet perverse, C++ implementations of the bogosort algorithm.

Bogosort NPM package
bogosort implementation for Node.js ecosystem.
* Max Sherma
Bogo-sort is Sort of Slow
June 2013
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Comparison sorts
Articles with example Python (programming language) code