Question
Two non-negative integers are stored as singly linked lists with digits in reverse order (least significant digit first), encoded as plain lists. Each node holds one digit 0-9. Add the two numbers and return the sum as a list of digits in the same reverse order, with no leading-(trailing-in-this-order) extra zeros except that the number 0 is represented as [0].
add_two_lists(a: list[int], b: list[int]) → list[int][[2,4,3],[5,6,4]]out[7,0,8]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.