Method reverse

leetcode/src/NextPermutation.java:33–41

(int[] nums, int start)

  }

  private void reverse(int[] nums, int start) {
    int rightPointer = nums.length - 1;

    while (start < rightPointer) {
      swap(nums, start, rightPointer);
      start++;
      rightPointer--;
    }
  }

  private void swap(int[] nums, int position1, int position2) {
    int old1 = nums[position1];