Chemical formula parser
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.
Implement
count_atoms(formula: str) → list[list]Examples
in
["H2O"]out[["H",2],["O",1]]What a strong answer looks like
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.
0:00 of about 35 min
solution.py
InputExpectedGot
["H2O"][["H",2],["O",1]]not run yetsample