
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



//recursively builds the permutations of permutable, appended to front, and returns the first sorted permutation it encounters
function permutations(front:Array, permutable:Array):Array {
	//If permutable has length 1, there is only one possible permutation. Check whether it's sorted
	if (permutable.length==1)
		return isSorted(front.concat(permutable));
	else
		//There are multiple possible permutations. Generate them.
		var i:uint=0,tmp:Array=null;
		do
		{
			tmp=permutations(front.concat([permutable[i]]),remove(permutable,i));
			i++;
		}while (i< permutable.length && tmp == null);
		//If tmp != null, it contains the sorted permutation. If it does not contain the sorted permutation, return null. Either way, return tmp.
		return tmp;
}
//returns the array if it's sorted, or null otherwise
function isSorted(data:Array):Array {
	for (var i:uint = 1; i < data.length; i++) 
		if (data[i]<data[i-1]) 
			return null;
	return data;
}
//returns a copy of array with the i'th element removed
function remove(array:Array, i:uint):Array {
	return array.filter(function(item,index,array){return(index !=i)}) ;
}
//wrapper around the permutation function to provide a more logical interface
function permutationSort(array:Array):Array {
	return permutations([],array);
}