Consider how to calculate the minimum number of operations when <code>nums1[n - 1]</code> and <code>nums2[n - 1]</code> are fixed (they are not swapped).

For each index <code>i</code>, there are only <code>3</code> possibilities: <ul> <li><code>nums1[i] <= nums1[n - 1] && nums2[i] <= nums2[n - 1]</code>. We don't need to swap them.</li> <li><code>nums1[i] <= nums2[n - 1] && nums2[i] <= nums1[n - 1]</code>. We have to swap them.</li> <li>Otherwise, there is no solution.</li> </ul>

There are <code>2</code> cases to determine the minimum number of operations: <ul> <li>The first case is the number of indices that need to be swapped when <code>nums1[n - 1]</code> and <code>nums2[n - 1]</code> are fixed.</li> <li>The second case is <code>1 +</code> the number of indices that need to be swapped when <code>nums1[n - 1]</code> and <code>nums2[n - 1]</code> are swapped.</li> </ul>

The answer is the minimum of both cases or <code>-1</code> if there is no solution in either case.