generating all the possible permutations in actionscript/flex

<?xml version="1.0" encoding="utf-8"?>

<mx:Application xmlns:mx="http://www.adobe.com/2006/mxml" layout="absolute" creationComplete="main()">

<mx:Script>

<![CDATA[

import mx.collections.ArrayCollection;

private function main():void {

var ac1:ArrayCollection = new ArrayCollection();

ac1.addItem(1);

ac1.addItem(2);

ac1.addItem(3);

ac1.addItem(4);

var output:ArrayCollection = permute(ac1);

for(var i:int = 0; i<output.length; ++i) {

var tmpAc:ArrayCollection = output.getItemAt(i) as ArrayCollection;

var singleLine:String = "";

for(var j:int = 0; j<tmpAc.length; ++j) {

singleLine += String(tmpAc[j])+" ";

}

trace(singleLine);

}

}

private function permute(inputListOfNumbers:ArrayCollection):ArrayCollection {

var output:ArrayCollection = new ArrayCollection();

if(inputListOfNumbers.length == 2) {

var ac1:ArrayCollection = new ArrayCollection();

ac1.addItem(inputListOfNumbers.getItemAt(0));

ac1.addItem(inputListOfNumbers.getItemAt(1));

output.addItem(ac1);

var ac1:ArrayCollection = new ArrayCollection();

ac1.addItem(inputListOfNumbers.getItemAt(1));

ac1.addItem(inputListOfNumbers.getItemAt(0));

output.addItem(ac1);

return output;

}

for(var i:int = 0; i<inputListOfNumbers.length; ++i) {

var otherThanIth:ArrayCollection = getElementsOtherThanIth(inputListOfNumbers,i);

var tmpRes:ArrayCollection = 

prependNumber(inputListOfNumbers.getItemAt(i) as int,permute(otherThanIth));

for(var j:int = 0; j<tmpRes.length; ++j) {

output.addItem(tmpRes.getItemAt(j));

}

}

return output;

}

private function prependNumber(i:int,ac1:ArrayCollection):ArrayCollection {

for(var j:int = 0; j<ac1.length; ++j) {

var tmpAc:ArrayCollection = ac1.getItemAt(j) as ArrayCollection;

tmpAc.addItemAt(i,0);

}

return ac1;

}

private function getElementsOtherThanIth(ac1:ArrayCollection,i:int):ArrayCollection {

var output:ArrayCollection = new ArrayCollection();

for(var j:int = 0; j<ac1.length; ++j) {

if(i != j) {

output.addItem(ac1.getItemAt(j));

}

}

return output;

}

]]>

</mx:Script>

</mx:Application>