Agree with Alpher.

Two pointer solution is not one pass solution.

Perhaps there is a confusion between one_pass and O(n) complexities.

Is two pointers an O(n) solution? Yes. Is it one_pass solution? Obviously not.

Moving two pointers, first one Length times and another one Len - n times is not different from get-length-of-the-list-first solution.

Basically they are the same: L (list Length) iterations to get length of the list and then Len - n iterations to get to the node which needs to be removed.

When n == 1 it's almost two passes, not one but still O(n).