
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:

O(n logn) sorts
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


Task

Implement a permutation sort, which proceeds by generating the possible permutations
of the input array/list until discovering the sorted one.

Pseudocode:

while not InOrder(list) do
    nextPermutation(list)
done



# Lexicographic permuter from "Permutations" task.
sub next_perm ( @a ) {
    my $j = @a.end - 1;
    $j-- while $j >= 1 and [>] @a[ $j, $j+1 ];
 
    my $aj = @a[$j];
    my $k  = @a.end;
    $k-- while [>] $aj, @a[$k];
 
    @a[ $j, $k ] .= reverse;
 
    my Int $r = @a.end;
    my Int $s = $j + 1;
    while $r > $s {
        @a[ $r, $s ] .= reverse;
        $r--;
        $s++;
    }
}
 
sub permutation_sort ( @a ) {
    my @n = @a.keys;
    my $perm_count = [*] 1 .. +@n; # Factorial
    for ^$perm_count {
        my @permuted_a = @a[ @n ];
        return @permuted_a if [le] @permuted_a;
        next_perm(@n);
    }
}
 
my @data  = < c b e d a >; # Halfway between abcde and edcba
say 'Input  = ' ~ @data;
say 'Output = ' ~ @data.&permutation_sort;
 