// Listing All Permutations (順列全列挙) // ported next_permutation() in C++(STL) package{ import flash.display.Sprite; import flash.text.TextField; public class Test extends Sprite{ public function Test() { var t:TextField = TextField(addChild(new TextField())); t.autoSize = "left"; var s:String = ""; var arr:Array = [1, 2, 3, 4]; do { s += arr.join(", ") + "\n"; } while (next_permutation(arr)); t.text = s; } private function next_permutation(arr:Array):Boolean { var len:int = arr.length; // fails if length is 0 or 1 if (len <= 1) return false; // search backward for (var i:int = len - 2; i >= 0; i--) { // find a index which satisfies arr[i] < arr[i + 1] if (arr[i] < arr[i + 1]) { // search backward again... // find a index which satisfies arr[i] < arr[j] for (var j:int = len - 1; j > i; j--) { if (arr[i] < arr[j]) break; } // swap arr[i] and arr[j] var tmp:Object = arr[j]; arr[j] = arr[i]; arr[i] = tmp; // reverse arr[i+1],arr[i+2],...,arr[len-1] for (j = 1; ; j++) { if (i + j >= len - j) break; tmp = arr[i + j]; arr[i + j] = arr[len - j]; arr[len - j] = tmp; } // found return true; } } // not found return false; } } }