Sorting algorithms/Permutation sort: Difference between revisions
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Pseudocode: |
Pseudocode: |
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while not InOrder(list) do newPermutation(list); |
while not InOrder(list) do newPermutation(list); |
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=={{header|C++}}== |
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Since <code>next_permutation</code> already returns whether the resulting sequence is sorted, the code is quite simple: |
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<cpp> |
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#include <algorithm> |
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template<typename ForwardIterator> |
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void permutation_sort(ForwardIterator begin, ForwardIterator end) |
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{ |
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while (std::next_permutation(begin, end)) |
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{ |
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// -- this block intentionally left empty -- |
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} |
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} |
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</cpp> |
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=={{header|Haskell}}== |
=={{header|Haskell}}== |
Revision as of 19:24, 8 May 2008
You are encouraged to solve this task according to the task description, using any language you may know.
Sorting Algorithm
This is a sorting algorithm. It may be applied to a set of data in order to sort it.
For comparing various sorts, see compare sorts.
For other sorting algorithms, see sorting algorithms, or:
Heap sort | Merge sort | Patience sort | Quick sort
O(n log2n) sorts
Shell Sort
O(n2) sorts
Bubble sort |
Cocktail sort |
Cocktail sort with shifting bounds |
Comb sort |
Cycle sort |
Gnome sort |
Insertion sort |
Selection sort |
Strand sort
other sorts
Bead sort |
Bogo sort |
Common sorted list |
Composite structures sort |
Custom comparator sort |
Counting sort |
Disjoint sublist sort |
External sort |
Jort sort |
Lexicographical sort |
Natural sorting |
Order by pair comparisons |
Order disjoint list items |
Order two numerical lists |
Object identifier (OID) sort |
Pancake sort |
Quickselect |
Permutation sort |
Radix sort |
Ranking methods |
Remove duplicate elements |
Sleep sort |
Stooge sort |
[Sort letters of a string] |
Three variable sort |
Topological sort |
Tree sort
Permutation sort.
Pseudocode:
while not InOrder(list) do newPermutation(list);
C++
Since next_permutation
already returns whether the resulting sequence is sorted, the code is quite simple:
<cpp>
- include <algorithm>
template<typename ForwardIterator>
void permutation_sort(ForwardIterator begin, ForwardIterator end)
{
while (std::next_permutation(begin, end)) { // -- this block intentionally left empty -- }
} </cpp>
Haskell
import Control.Monad permutationSort l = head $ do p <- permute l if sorted p then return p else mzero sorted (e1 : e2 : r) = e1 <= e2 && sorted (e2 : r) sorted _ = True permute [] = return [] permute (h:t) = do { t' <- permute t ; insert h t' } insert e [] = return [e] insert e l@(h : t) = return (e : l) `mplus` do { t' <- insert e t ; return (h : t') }
Prolog
permutation_sort(L,S) :- permutation(L,S), sorted(S). sorted([]). sorted([_]). sorted([X,Y|ZS]) :- X =< Y, sorted([Y|ZS]). permutation([],[]). permutation([X|XS],YS) :- permutation(XS,ZS), select(X,YS,ZS).
Scheme
<scheme> (define (insertions e list)
(if (null? list) (cons (cons e list) list) (cons (cons e list) (map (lambda (tail) (cons (car list) tail)) (insertions e (cdr list))))))
(define (permutations list)
(if (null? list) (cons list list) (apply append (map (lambda (permutation) (insertions (car list) permutation)) (permutations (cdr list))))))
(define (sorted? list)
(cond ((null? list) #t) ((null? (cdr list)) #t) ((<= (car list) (cadr list)) (sorted? (cdr list))) (else #f)))
(define (permutation-sort list)
(let loop ((permutations (permutations list))) (if (sorted? (car permutations)) (car permutations) (loop (cdr permutations)))))
</scheme>