G'day jdporter,

I liked the general thinking behind this; however, I see two issues.

"# assumption: @nums are already sorted."

There is no requirement for the input list to be sorted. As an example, see "1. Two Sum" Example 2:

Input: nums = [3,2,4], target = 6
Output: [1,2]
[download]

If you did "add a sorting step", you could potentially change the result:

Input: nums = [2,3,4], target = 6
Output: [0,2]
[download]

"# caveat: the nums in the list might not be uniq!!!"

Again, there's no requirement for this uniqueness. See Example 3:

Input: nums = [3,3], target = 6
Output: [0,1]
[download]

As far as I can tell (by inspection) your code produces a correct result with this input. An input of [3,1,1,1,3] would produce a correct result: [0,4]. An input of [3,3,3] would be invalid from the outset, because there's more than one possible solution: [0,1], [0,2] and [1,2] — whatever code you (or anyone) wrote would be immaterial for this input.