Question
A packing line has a fixed row of slots holding item codes. When a new item enters at the left end, every item shifts one slot to the right and the item in the last slot drops off the end of the line. Given the current slots and the entering item, return the row after the shift. A row with no slots stays empty. Example: [1, 2, 3] with new item 9 becomes [9, 1, 2].
line_shift(slots: list[int], item: int) → list[int][[1,2,3],9]out[9,1,2]State your approach and its time/space complexity out loud before you optimize. Handle the edge cases (empty input, duplicates, overflow), and say why you chose this over the brute force. Green tests are the floor, not the grade.
Vibe coding: describe the solution in plain language (or narrate it) and the coach grades your approach. Generating runnable code from your description is coming next.