Question
A string is an additive number if its digits can be split into at least three non-negative integers where every number after the first two equals the sum of the two preceding ones. Numbers in the sequence may not have a leading zero (so '0' alone is fine but '03' is not). Given a string num of digits (length 1..35), return whether it is an additive number. Return a boolean.
is_additive_number(num: str) → bool["112358"]outtrueState 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.