Question
Given a chemical formula as a string, return the count of each atom. An atom name starts with an uppercase letter followed by zero or more lowercase letters. A name or a parenthesized group may be followed by a multiplicity (an integer >= 2; absent means 1), e.g. `Mg(OH)2`. Groups may nest. Return a list of `[name, count]` pairs sorted alphabetically by name.
count_atoms(formula: str) → list[list]["H2O"]out[["H",2],["O",1]]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.