calculateNextPermutation();
      return next;
    }

    void calculateNextPermutation() {
      j = list.size() - 1;
      int s = 0;

      // Handle the special case of an empty list. Skip the calculation of the
      // next permutation.
      if (j == -1) {
        return;
      }

      while (true) {
        int q = c[j] + o[j];

      calculateNextPermutation();
      return next;
    }

    void calculateNextPermutation() {
      j = list.size() - 1;
      int s = 0;

      // Handle the special case of an empty list. Skip the calculation of the
      // next permutation.
      if (j == -1) {
        return;
      }

      while (true) {
        int q = c[j] + o[j];