Unimpressive/Unimpressive Code

    public static boolean permutation(List values, int index) {

        return permutation(values, values.size() - 1, index);

    }

    private static boolean permutation(List values, int n, int index) {

        if ((index == 0) || (n == 0)) {

            return (index == 0);

        }

        Collections.swap(values, n, n - (index % n));

        return permutation(values, n - 1, index / n);

    }

Give it a list, and an index and it will do the permutatation associated with that index. It runs out of integers at 12 items as 12! > Integer.MAX_VALUE